diff --git a/c2pa/cai_tool.py b/c2pa/cai_tool.py
index ef82998..97704b0 100644
--- a/c2pa/cai_tool.py
+++ b/c2pa/cai_tool.py
@@ -19,7 +19,6 @@
 import hashlib
 import json
 import os
-import sys
 
 import multibase
 import multihash
@@ -48,7 +47,7 @@ def parse_json(fname):
     return output
 
 
-def convert_to_hex(label, indent = 0, sec_indent = -1):
+def convert_to_hex(label, indent=0, sec_indent=-1):
     '''Convert label into hexadecimals
     '''
     if sec_indent == -1:
@@ -130,7 +129,7 @@ def get_content_lbox(fname):
     data = parse_json(fname)
 
     t_box_size = len(convert_to_hex('json'))
-    
+
     payload_size = len(convert_to_hex(data))
 
     total_size = 4 + t_box_size + payload_size
@@ -144,12 +143,12 @@ def get_uuid_content_box():
     '''Generate l_box for size for uuid content
     '''
     t_box_size = len(convert_to_hex('uuid'))
-    
+
     data_hex = ['63', '61', '73', '67', '00', '11', '00', '10', '80', '00', '00', 'aa', '00', '38', '9b', '71']
     data_hex_size = len(data_hex)
 
     # signature 1: placeholder signature data as mockup
-    # payload_data = ['73', '69', '67', '6e', '61', '74', '75', '72', '65', '20', '70', '6c', '61', '63', '65', '68', '6f', '6c', '64', '65', '72', '3a', '63', '62', '2e', '73', '74', '61', '72', '6c', '69', '6e', '67', '5f', '31', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20']
+    # payload_data = ['73', '69', '67', '6e', '61', '74', '75', '72', '65', '20', '70', '6c', '61', '63', '65', '68', '6f', '6c', '64', '65', '72', '3a', '63', '62', '2e', '73', '74', '61', '72', '6c', '69', '6e', '67', '5f', '31', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20'] # noqa E501
     # signature 2: real example signature
     payload_data = ['00', '87', '65', '0C', '94', '6D', 'EE', '53', '05', 'B2', 'D8', '87', '19', 'AD', '30', 'A9',
                     '9C', 'AB', 'CF', '3D', 'A2', '00', 'C2', '3D', '61', '71', '0B', 'EB', 'E7', '24', 'D0', 'CD',
@@ -256,7 +255,7 @@ def create_uuid_box(l_box):
     '''
     t_box = convert_to_hex('uuid')
     data_hex = ['63', '61', '73', '67', '00', '11', '00', '10', '80', '00', '00', 'aa', '00', '38', '9b', '71']
-    # payload_data = ['73', '69', '67', '6e', '61', '74', '75', '72', '65', '20', '70', '6c', '61', '63', '65', '68', '6f', '6c', '64', '65', '72', '3a', '63', '62', '2e', '73', '74', '61', '72', '6c', '69', '6e', '67', '5f', '31', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20']
+    # payload_data = ['73', '69', '67', '6e', '61', '74', '75', '72', '65', '20', '70', '6c', '61', '63', '65', '68', '6f', '6c', '64', '65', '72', '3a', '63', '62', '2e', '73', '74', '61', '72', '6c', '69', '6e', '67', '5f', '31', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20', '20'] # noqa E501
     payload_data = ['00', '87', '65', '0C', '94', '6D', 'EE', '53', '05', 'B2', 'D8', '87', '19', 'AD', '30', 'A9',
                     '9C', 'AB', 'CF', '3D', 'A2', '00', 'C2', '3D', '61', '71', '0B', 'EB', 'E7', '24', 'D0', 'CD',
                     'B1', 'CC', 'E5', '0C', '3A', '74', '26', '71', '5A', '86', '04', 'DB', '36', '55', 'C5', '30',
@@ -302,9 +301,20 @@ def create_injection_block(cai_block, store_block, assertion_store, assertion, c
 
     header = ['FF', 'EB']
     c_box = convert_to_hex('JP')
-    box_remain = ['00', '01', '00', '00', '00','01']
-
-    block = header + l_box + c_box + box_remain + cai_block + store_block + assertion_store + assertion + claim + signature
+    box_remain = ['00', '01', '00', '00', '00', '01']
+
+    block = (
+        header +
+        l_box +
+        c_box +
+        box_remain +
+        cai_block +
+        store_block +
+        assertion_store +
+        assertion +
+        claim +
+        signature
+    )
 
     return block
 
@@ -421,9 +431,20 @@ def create_complete(cai_l_box, cai_block, store_block, assertion_block, assertio
 
     header = ['FF', 'EB']
     c_box = convert_to_hex('JP')
-    box_remain = ['00', '01', '00', '00', '00','01']
-
-    final_cai_block = header + l_box + c_box + box_remain + cai_block + store_block + assertion_block + assertions + claim_block + signature_block
+    box_remain = ['00', '01', '00', '00', '00', '01']
+
+    final_cai_block = (
+        header +
+        l_box +
+        c_box +
+        box_remain +
+        cai_block +
+        store_block +
+        assertion_block +
+        assertions +
+        claim_block +
+        signature_block
+    )
 
     return final_cai_block
 
diff --git a/c2pa/core.py b/c2pa/core.py
index 37eab3a..c8dc0d9 100644
--- a/c2pa/core.py
+++ b/c2pa/core.py
@@ -25,12 +25,10 @@
 from Crypto.PublicKey import RSA
 from Crypto.Signature import PKCS1_v1_5
 
-from cai.jumbf import Box
 from cai.jumbf import ContentBox
 from cai.jumbf import DescriptionBox
 from cai.jumbf import SuperBox
 
-from cai.jumbf import create_json_superbox
 from cai.jumbf import json_to_bytes
 
 from endesive import plain
@@ -40,10 +38,10 @@
 '''
 
 Cai_content_types = {
-    'claim_block'    : '6361636200110010800000aa00389b71',
-    'store'          : '6361737400110010800000aa00389b71',
+    'claim_block'    : '6361636200110010800000aa00389b71', # noqa E203
+    'store'          : '6361737400110010800000aa00389b71', # noqa E203
     'assertion_store': '6361617300110010800000aa00389b71',
-    'claim'          : '6361636c00110010800000aa00389b71',
+    'claim'          : '6361636c00110010800000aa00389b71', # noqa E203
     'claim_signature': '6361736700110010800000aa00389b71',
 }
 
@@ -152,6 +150,7 @@ def create_claim(self, assertion_store,
             claim['parent_claim'] = parent_claim
         return claim
 
+
 class CaiClaimEndesiveSignature(SuperBox):
     def __init__(self, claim, key):
         super(CaiClaimEndesiveSignature, self).__init__()
@@ -169,6 +168,7 @@ def create_endesive_signature(self, claim, key):
         payload = bytes.fromhex(uuid) + signature
         return payload
 
+
 class CaiClaimCMSSignature(SuperBox):
     def __init__(self, claim, key):
         super(CaiClaimCMSSignature, self).__init__()
@@ -256,4 +256,4 @@ def __init__(self):
         super(CaiClaimBlock, self).__init__()
         self.description_box = DescriptionBox(
                                    content_type=Cai_content_types['claim_block'],
-                                   label='cai')
\ No newline at end of file
+                                   label='cai')
diff --git a/c2pa/jumbf.py b/c2pa/jumbf.py
index 49123ba..6f7a701 100644
--- a/c2pa/jumbf.py
+++ b/c2pa/jumbf.py
@@ -26,9 +26,9 @@
 # Spec B.1
 Jumbf_content_types = {
     'codestream': '6579d6fbdba2446bb2ac1b82feeb89d1',
-    'xml'       : '786d6c2000110010800000aa00389b71',
-    'json'      : '6a736f6e00110010800000aa00389b71',
-    'uuid'      : '7575696400110010800000aa00389b71',
+    'xml'       : '786d6c2000110010800000aa00389b71', # noqa E203
+    'json'      : '6a736f6e00110010800000aa00389b71', # noqa E203
+    'uuid'      : '7575696400110010800000aa00389b71', # noqa E203
 }
 
 
@@ -45,7 +45,7 @@ def get_size(self):
         # Calculate box size dynamically.
         # 8 is from l_box (4) + t_box (4)
         return 8 + len(self.payload)
-    
+
     def set_payload(self):
         pass
 
@@ -173,9 +173,9 @@ def convert_bytes(self):
 
 
 def create_single_content_superbox(content=b'',
-                         t_box_type='',
-                         content_type='',
-                         label=''):
+                                   t_box_type='',
+                                   content_type='',
+                                   label=''):
     c_box = ContentBox(t_box_type=t_box_type)
     c_box.payload = content
     d_box = DescriptionBox(content_type=content_type, label=label)
@@ -202,7 +202,7 @@ def create_codestream_superbox(content=b'', label=''):
 
 
 def json_to_bytes(json_object):
-    return json.dumps(json_object, separators=(',',':')).encode('utf-8')
+    return json.dumps(json_object, separators=(',', ':')).encode('utf-8')
 
 
 def get_app11_marker_segment_headers(data_bytes):
@@ -211,24 +211,24 @@ def get_app11_marker_segment_headers(data_bytes):
     headers = {}
     for offset in offsets:
         try:
-            ci = data_bytes[offset + 4 : offset + 6].decode('utf-8')
+            ci = data_bytes[offset + 4: offset + 6].decode('utf-8')
         except Exception as e:
-            print('Find App11 marker, and fail to get CI')
+            print(f'Find App11 marker, and fail to get CI. Exception: {e}')
             ci = None
         try:
-            tbox = data_bytes[offset + 16 : offset + 20].decode('utf-8')
+            tbox = data_bytes[offset + 16: offset + 20].decode('utf-8')
         except Exception as e:
-            print('Find App11 marker, and fail to get TBox')
+            print(f'Find App11 marker, and fail to get TBox. Exception: {e}')
             tbox = None
 
         if ci == 'JP' and tbox == 'jumb':
             header = {}
-            header['le']     = int.from_bytes(data_bytes[offset + 2 : offset + 4], byteorder='big')
-            header['ci']     = data_bytes[offset + 4 : offset + 6].decode('utf-8')
-            header['en']     = int.from_bytes(data_bytes[offset + 6 : offset + 8], byteorder='big')
-            header['z']      = int.from_bytes(data_bytes[offset + 8 : offset + 12], byteorder='big')
-            header['lbox']   = int.from_bytes(data_bytes[offset + 12 : offset + 16], byteorder='big')
-            header['tbox']   = data_bytes[offset + 16 : offset + 20].decode('utf-8')
+            header['le'] = int.from_bytes(data_bytes[offset + 2: offset + 4], byteorder='big')
+            header['ci'] = data_bytes[offset + 4: offset + 6].decode('utf-8')
+            header['en'] = int.from_bytes(data_bytes[offset + 6: offset + 8], byteorder='big')
+            header['z'] = int.from_bytes(data_bytes[offset + 8: offset + 12], byteorder='big')
+            header['lbox'] = int.from_bytes(data_bytes[offset + 12: offset + 16], byteorder='big')
+            header['tbox'] = data_bytes[offset + 16: offset + 20].decode('utf-8')
             header['offset'] = offset
 
             # passive protection to skip illegal or empty segment
@@ -236,4 +236,4 @@ def get_app11_marker_segment_headers(data_bytes):
                 headers[header['z']] = header
         else:
             print('Unknown CI ({0}) or TBox ({1}) of offset {2}'.format(ci, tbox, hex(offset)))
-    return headers
\ No newline at end of file
+    return headers
diff --git a/c2pa/starling.py b/c2pa/starling.py
index 9d6e7a5..d971f08 100644
--- a/c2pa/starling.py
+++ b/c2pa/starling.py
@@ -19,7 +19,6 @@
 import os
 
 from c2pa.core import CaiClaimBlock
-from c2pa.core import CaiClaimCMSSignature
 from c2pa.core import CaiStore
 from c2pa.jumbf import App11Box
 
@@ -36,6 +35,7 @@
 '''Starling CLI tool to generate CAI metadata.
 '''
 
+
 class Starling(object):
     def __init__(self,
                  media_bytes,
@@ -161,13 +161,13 @@ def multiple_claims_injection(self):
 
         # re-construct Claim Block payload
         claim_block_payload = bytearray()
-        ## App11 Length of Marker Segment (the Le parameter) value is 8 ~ 65535.
-        ## App11 Packet Sequence number (the Z parameter) value is 1 ~ 2^32-1.
-        ## The Claim Block maximum size will be ~= 2^48 B ~= 280 TB.
+        # App11 Length of Marker Segment (the Le parameter) value is 8 ~ 65535.
+        # App11 Packet Sequence number (the Z parameter) value is 1 ~ 2^32-1.
+        # The Claim Block maximum size will be ~= 2^48 B ~= 280 TB.
         for i in range(1, header_number + 1):
             payload_start = self.app11_headers[i]['offset'] + 20
             payload_end = payload_start + (self.app11_headers[i]['le'] - 18)
-            payload = self.raw_bytes[payload_start : payload_end]
+            payload = self.raw_bytes[payload_start: payload_end]
             claim_block_payload += payload
         store_bytes = cai_store.convert_bytes()
 
@@ -178,27 +178,31 @@ def multiple_claims_injection(self):
         updated_app11_segment = App11Box(en=last_en)
         updated_app11_segment.payload = updated_claim_block_bytes
 
-        ## Assuming that current CAI data consists of 3 App11 segments.
-        ##
-        ## +-- starting point
-        ## v
-        ## +-------+----+----+------+-----+------+------+-------------------------------+
-        ## | APP11 | Le | CI | En=1 | Z=1 | LBox | TBox | Payload (Claim Block, part 1) |
-        ## +-------+----+----+------+-----+------+------+-------------------------------+
-        ## | APP11 | Le | CI | En=1 | Z=2 | LBox | TBox | Payload (Claim Block, part 2) |
-        ## +-------+----+----+------+-----+------+------+-------------------------------+
-        ## | APP11 | Le | CI | En=1 | Z=3 | LBox | TBox | Payload (Claim Block, part 3) |
-        ## +-------+----+----+------+-----+------+------+-------------------------------+
-        ##                                                                              ^
-        ##                                                               ending point --+
-        ##
-        ## starting point of current CAI data
+        # Assuming that current CAI data consists of 3 App11 segments.
+        #
+        # +-- starting point
+        # v
+        # +-------+----+----+------+-----+------+------+-------------------------------+
+        # | APP11 | Le | CI | En=1 | Z=1 | LBox | TBox | Payload (Claim Block, part 1) |
+        # +-------+----+----+------+-----+------+------+-------------------------------+
+        # | APP11 | Le | CI | En=1 | Z=2 | LBox | TBox | Payload (Claim Block, part 2) |
+        # +-------+----+----+------+-----+------+------+-------------------------------+
+        # | APP11 | Le | CI | En=1 | Z=3 | LBox | TBox | Payload (Claim Block, part 3) |
+        # +-------+----+----+------+-----+------+------+-------------------------------+
+        #                                                                              ^
+        #                                                               ending point --+
+        #
+        # starting point of current CAI data
         update_range_s = self.app11_headers[1]['offset']
-        ## ending point of current CAI data
+        # ending point of current CAI data
         update_range_e = self.app11_headers[header_number]['offset'] + self.app11_headers[header_number]['le'] + 2
 
         # save CAI-injected media
-        data_bytes = self.raw_bytes[:update_range_s] + updated_app11_segment.convert_bytes() + self.raw_bytes[update_range_e:]
+        data_bytes = (
+            self.raw_bytes[:update_range_s] +
+            updated_app11_segment.convert_bytes() +
+            self.raw_bytes[update_range_e:]
+        )
         cai_data_bytes = insert_xmp_key(data_bytes, store_label=self.store_label)
         return cai_data_bytes
 
@@ -283,10 +287,11 @@ def main():
     # private key for signature
     if key_filepath != '':
         with open(key_filepath, 'rb') as f:
-            if type_sig=='cms':
+            if type_sig == 'cms':
                 key = f.read()
-            elif type_sig=='endesive':
-                # load_key_and_certificates second parameter is password to decrypt the data. Can be set to None of PKCS12 is not encrypted
+            elif type_sig == 'endesive':
+                # load_key_and_certificates second parameter is password to decrypt the data.
+                # Can be set to None of PKCS12 is not encrypted
                 # https://cryptography.io/en/latest/hazmat/primitives/asymmetric/serialization.html
                 key = pkcs12.load_key_and_certificates(f.read(), b'', backends.default_backend())
             else:
@@ -314,4 +319,4 @@ def main():
 
 
 if __name__ == "__main__":
-    main()   
\ No newline at end of file
+    main()
diff --git a/data/Keys/endesive_sig.py b/data/Keys/endesive_sig.py
index 8594122..6f50716 100644
--- a/data/Keys/endesive_sig.py
+++ b/data/Keys/endesive_sig.py
@@ -7,7 +7,8 @@ def main():
     with open('demo2_user1.p12', 'rb') as fp:
         p12 = pkcs12.load_key_and_certificates(fp.read(), b'1234', backends.default_backend())
     unsigned = open('plain-unsigned.txt', 'rb').read()
-    signed = plain.sign(unsigned,
+    signed = plain.sign(
+        unsigned,
         p12[0], p12[1], p12[2],
         'sha256',
         attrs=True
@@ -15,4 +16,4 @@ def main():
     open('plain-signed-attr.txt', 'wb').write(signed)
 
 
-main()
\ No newline at end of file
+main()
diff --git a/data/Keys/verify_sig.py b/data/Keys/verify_sig.py
index ee78579..eaeecc5 100644
--- a/data/Keys/verify_sig.py
+++ b/data/Keys/verify_sig.py
@@ -1,5 +1,6 @@
 from endesive import plain
 
+
 def main():
     trusted_cert_pems = (open('demo2_ca.crt.pem', 'rt').read(),)
     unsigned = open('plain-unsigned.txt', 'rb').read()
@@ -12,5 +13,6 @@ def main():
     print('signature ok?', signatureok)
     print('hash ok?', hashok)
 
+
 if __name__ == "__main__":
-    main()
\ No newline at end of file
+    main()
diff --git a/setup.py b/setup.py
index 6606525..5540741 100644
--- a/setup.py
+++ b/setup.py
@@ -1,5 +1,3 @@
-import subprocess
-
 from setuptools import setup
 from setuptools import find_packages
 
diff --git a/tests/test_core.py b/tests/test_core.py
index ed2cbf8..0541650 100644
--- a/tests/test_core.py
+++ b/tests/test_core.py
@@ -1,5 +1,3 @@
-import io
-import json
 import unittest
 
 from cai.core import CaiAssertionStore
@@ -76,7 +74,7 @@ def test_cai_claim(self):
                          bytes.fromhex(testing_claim))
 
     def test_cai_claim_signature(self):
-        testing_claim_signature = (
+        testing_claim_signature = ( # noqa F841
             '000000446a756d62000000276a756d646361736700110010800000aa00389b71'
             '036361692e7369676e617475726500000000156a736f6e7b22666f6f223a2262'
             '6172227d'
@@ -90,11 +88,11 @@ def test_cai_claim_signature(self):
         cai_claim_signature.description_box.print_box()
         cai_claim_signature.print_box()
 
-        #self.assertEqual(cai_claim_signature.convert_bytes(),
+        # self.assertEqual(cai_claim_signature.convert_bytes(),
         #                 bytes.fromhex(testing_claim_signature))
 
     def test_cai_store(self):
-        testing_store = (
+        testing_store = ( # noqa F841
             '000001296a756d62000000276a756d646361737400110010800000aa00389b71'
             '0363622e737461726c696e675f3100000000766a756d62000000286a756d6463'
             '61617300110010800000aa00389b71036361692e617373657274696f6e730000'
@@ -122,11 +120,11 @@ def test_cai_store(self):
         cai_store.description_box.print_box()
         cai_store.print_box()
 
-        #self.assertEqual(cai_store.convert_bytes(),
+        # self.assertEqual(cai_store.convert_bytes(),
         #                 bytes.fromhex(testing_store))
 
     def test_cai_claim_block(self):
-        testing_claim_block = (
+        testing_claim_block = ( # noqa F841
             '0000014e6a756d620000001d6a756d646361636200110010800000aa00389b71'
             '0363616900000001296a756d62000000276a756d646361737400110010800000'
             'aa00389b710363622e737461726c696e675f3100000000766a756d6200000028'
@@ -157,11 +155,11 @@ def test_cai_claim_block(self):
         cai_claim_block.description_box.print_box()
         cai_claim_block.print_box()
 
-        #self.assertEqual(cai_claim_block.convert_bytes(),
+        # self.assertEqual(cai_claim_block.convert_bytes(),
         #                 bytes.fromhex(testing_claim_block))
 
     def test_app11_segment(self):
-        testing_app11_segment = (
+        testing_app11_segment = ( # noqa F841
             'ffeb01584a500001000000010000014e6a756d620000001d6a756d6463616362'
             '00110010800000aa00389b710363616900000001296a756d62000000276a756d'
             '646361737400110010800000aa00389b710363622e737461726c696e675f3100'
@@ -191,7 +189,7 @@ def test_app11_segment(self):
         app11_segment.payload = cai_claim_block.convert_bytes()
         print('\tbytes:', app11_segment.convert_bytes().hex())
 
-        #self.assertEqual(app11_segment.convert_bytes(),
+        # self.assertEqual(app11_segment.convert_bytes(),
         #                 bytes.fromhex(testing_app11_segment))
 
 
diff --git a/tests/test_jumbf.py b/tests/test_jumbf.py
index 2f92220..38ee895 100644
--- a/tests/test_jumbf.py
+++ b/tests/test_jumbf.py
@@ -102,7 +102,7 @@ def test_jumbf_hello_world(self):
             '223a22626172227d'
         )
 
-        data = {"foo":"bar"}
+        data = {"foo": "bar"}
         f = io.BytesIO(json.dumps(data, separators=(',', ':')).encode('utf-8'))
         data_bytes = f.read()
 
diff --git a/utils/c2pa_hello_world.py b/utils/c2pa_hello_world.py
index 39eabf1..bf93f3b 100755
--- a/utils/c2pa_hello_world.py
+++ b/utils/c2pa_hello_world.py
@@ -44,8 +44,8 @@
 photo_filename = 'meimei-fried-chicken.jpg'
 
 # multi-claim injection
-#photo_url = 'https://ipfs.io/ipfs/QmPa8Dokcjcouv1KYrXn1cYA6XLACDBPVmnaMZ4un8K54L'
-#photo_filename = 'meimei-nbj.jpg'
+# photo_url = 'https://ipfs.io/ipfs/QmPa8Dokcjcouv1KYrXn1cYA6XLACDBPVmnaMZ4un8K54L'
+# photo_filename = 'meimei-nbj.jpg'
 
 photo_bytes = requests.get(photo_url).content
 
@@ -108,4 +108,4 @@
 fname, fext = os.path.splitext(photo_filename)
 fpath = fname + '-cai' + fext
 with open(fpath, 'wb') as f:
-    f.write(starling_cai_bytes)
\ No newline at end of file
+    f.write(starling_cai_bytes)
diff --git a/utils/c2pa_multiple_injection.py b/utils/c2pa_multiple_injection.py
index 3d8fb79..e0dca6a 100755
--- a/utils/c2pa_multiple_injection.py
+++ b/utils/c2pa_multiple_injection.py
@@ -34,8 +34,6 @@
 import os
 import sys
 
-import requests
-
 from c2pa.jumbf import json_to_bytes
 from c2pa.starling import Starling
 
diff --git a/utils/digital-signature/cms/digital_signature.py b/utils/digital-signature/cms/digital_signature.py
index 13e8476..66c2ff2 100644
--- a/utils/digital-signature/cms/digital_signature.py
+++ b/utils/digital-signature/cms/digital_signature.py
@@ -5,9 +5,11 @@
 
 
 def usage():
-    print("Usage: \n"
-            "digi-sig -s  <priv-key> <data> <signature-file> \n"
-            "digi-sig -v  <PUB-key> <data> <signature-file> \n")
+    print(
+        "Usage: \n"
+        "digi-sig -s  <priv-key> <data> <signature-file> \n"
+        "digi-sig -v  <PUB-key> <data> <signature-file> \n"
+    )
 
 
 if (len(sys.argv) < 5):
@@ -26,7 +28,8 @@ def generate_signature(key, data, sig_f):
     rsa = RSA.importKey(key)
     signer = PKCS1_v1_5.new(rsa)
     signature = signer.sign(h)
-    with open(sig_f, 'wb') as f: f.write(signature)
+    with open(sig_f, 'wb') as f:
+        f.write(signature)
 
 
 def verify_signature(key, data, sig_f):
@@ -34,7 +37,8 @@ def verify_signature(key, data, sig_f):
     h = SHA256.new(data)
     rsa = RSA.importKey(key)
     signer = PKCS1_v1_5.new(rsa)
-    with open(sig_f, 'rb') as f: signature = f.read()
+    with open(sig_f, 'rb') as f:
+        signature = f.read()
 
     if (signer.verify(h, signature)):
         rsp = 'Success'
@@ -45,8 +49,10 @@ def verify_signature(key, data, sig_f):
 
 def main():
     # Read all file contents
-    with open(key_f, 'rb') as f: key = f.read()
-    with open(data_f, 'rb') as f: data = f.read()
+    with open(key_f, 'rb') as f:
+        key = f.read()
+    with open(data_f, 'rb') as f:
+        data = f.read()
 
     if (op == "-s"):
         # Generate Signature
@@ -55,9 +61,9 @@ def main():
         # Verify Signature
         verify_signature(key, data, sig_f)
     else:
-        #Error
+        # Error
         usage()
 
 
 if __name__ == "__main__":
-    main()
\ No newline at end of file
+    main()
diff --git a/utils/digital-signature/digital_signature.py b/utils/digital-signature/digital_signature.py
index 13e8476..66c2ff2 100644
--- a/utils/digital-signature/digital_signature.py
+++ b/utils/digital-signature/digital_signature.py
@@ -5,9 +5,11 @@
 
 
 def usage():
-    print("Usage: \n"
-            "digi-sig -s  <priv-key> <data> <signature-file> \n"
-            "digi-sig -v  <PUB-key> <data> <signature-file> \n")
+    print(
+        "Usage: \n"
+        "digi-sig -s  <priv-key> <data> <signature-file> \n"
+        "digi-sig -v  <PUB-key> <data> <signature-file> \n"
+    )
 
 
 if (len(sys.argv) < 5):
@@ -26,7 +28,8 @@ def generate_signature(key, data, sig_f):
     rsa = RSA.importKey(key)
     signer = PKCS1_v1_5.new(rsa)
     signature = signer.sign(h)
-    with open(sig_f, 'wb') as f: f.write(signature)
+    with open(sig_f, 'wb') as f:
+        f.write(signature)
 
 
 def verify_signature(key, data, sig_f):
@@ -34,7 +37,8 @@ def verify_signature(key, data, sig_f):
     h = SHA256.new(data)
     rsa = RSA.importKey(key)
     signer = PKCS1_v1_5.new(rsa)
-    with open(sig_f, 'rb') as f: signature = f.read()
+    with open(sig_f, 'rb') as f:
+        signature = f.read()
 
     if (signer.verify(h, signature)):
         rsp = 'Success'
@@ -45,8 +49,10 @@ def verify_signature(key, data, sig_f):
 
 def main():
     # Read all file contents
-    with open(key_f, 'rb') as f: key = f.read()
-    with open(data_f, 'rb') as f: data = f.read()
+    with open(key_f, 'rb') as f:
+        key = f.read()
+    with open(data_f, 'rb') as f:
+        data = f.read()
 
     if (op == "-s"):
         # Generate Signature
@@ -55,9 +61,9 @@ def main():
         # Verify Signature
         verify_signature(key, data, sig_f)
     else:
-        #Error
+        # Error
         usage()
 
 
 if __name__ == "__main__":
-    main()
\ No newline at end of file
+    main()
diff --git a/utils/digital-signature/endesive/endesive-sign.py b/utils/digital-signature/endesive/endesive-sign.py
index 3988460..f125dc7 100644
--- a/utils/digital-signature/endesive/endesive-sign.py
+++ b/utils/digital-signature/endesive/endesive-sign.py
@@ -3,32 +3,40 @@
 from cryptography.hazmat.primitives.serialization import pkcs12
 from endesive import plain
 
+
 def usage():
-    print("Usage: \n"
-            "endesive-sig -s <p12> <unsigned claim> <signed> \n"
-            "endesive-verify -v <crt.pem> <unsigned claim> <signed> \n")
+    print(
+        "Usage: \n"
+        "endesive-sig -s <p12> <unsigned claim> <signed> \n"
+        "endesive-verify -v <crt.pem> <unsigned claim> <signed> \n"
+    )
+
 
 if (len(sys.argv) < 5):
     usage()
     quit()
 
+
 op = sys.argv[1]
 key_f = sys.argv[2]
 data_f = sys.argv[3]
 sign_f = sys.argv[4]
 
+
 def generate_signature(key, data, signed):
     print("Generating Signature")
     with open(key, 'rb') as fp:
         p12 = pkcs12.load_key_and_certificates(fp.read(), b'', backends.default_backend())
     datau = open(data, 'rb').read()
-    datas = plain.sign(datau,
+    datas = plain.sign(
+        datau,
         p12[0], p12[1], p12[2],
         'sha256',
         attrs=True
     )
     open(signed, 'wb').write(datas)
 
+
 def verfy_signature(key, data, signed):
     print("Verifying Signature")
     trusted_cert_pems = (open(key, 'rt').read(),)
@@ -39,8 +47,9 @@ def verfy_signature(key, data, signed):
     print('hash ok?', hashok)
     print('cert ok?', certok)
 
+
 def main():
-    
+
     if (op == '-s'):
         # Generate Signature
         generate_signature(key_f, data_f, sign_f)
@@ -53,4 +62,4 @@ def main():
 
 
 if __name__ == "__main__":
-    main()
\ No newline at end of file
+    main()
diff --git a/utils/digital-signature/hex2bin.py b/utils/digital-signature/hex2bin.py
index 553e217..2f3c761 100644
--- a/utils/digital-signature/hex2bin.py
+++ b/utils/digital-signature/hex2bin.py
@@ -22,4 +22,4 @@ def main():
 
 
 if __name__ == '__main__':
-    main()
\ No newline at end of file
+    main()
diff --git a/utils/encode_hashlink.py b/utils/encode_hashlink.py
index f5a6988..c8f6af2 100644
--- a/utils/encode_hashlink.py
+++ b/utils/encode_hashlink.py
@@ -45,4 +45,4 @@ def parse_args():
         print('Input file: {0}\nhashlink param: {1}'.format(
             os.path.basename(filepath),
             encode_hashlink(data_bytes, to_hexstr=True)
-        ))
\ No newline at end of file
+        ))
diff --git a/utils/get_marker_index.py b/utils/get_marker_index.py
index 74e5e31..dacf5e9 100644
--- a/utils/get_marker_index.py
+++ b/utils/get_marker_index.py
@@ -12,10 +12,10 @@
 
 final_lbox = 0
 for offset in offsets:
-    Le   = int.from_bytes(f[offset + 2 : offset + 4], byteorder='big')
-    En   = int.from_bytes(f[offset + 6 : offset + 8], byteorder='big')
-    Z    = int.from_bytes(f[offset + 8 : offset + 12], byteorder='big')
-    LBox = int.from_bytes(f[offset + 12 : offset + 16], byteorder='big')
+    Le = int.from_bytes(f[offset + 2: offset + 4], byteorder='big')
+    En = int.from_bytes(f[offset + 6: offset + 8], byteorder='big')
+    Z = int.from_bytes(f[offset + 8: offset + 12], byteorder='big')
+    LBox = int.from_bytes(f[offset + 12: offset + 16], byteorder='big')
 
     print('# Offset: {0}, Le: {1}, En: {2}, Z (seq): {3}, LBox: {4}'.format(
         offset, Le, En, Z, LBox))