diff --git a/megaflow/__pycache__/__init__.cpython-310.pyc b/megaflow/__pycache__/__init__.cpython-310.pyc
index 8a8efc2..f9c827b 100644
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diff --git a/megaflow/common/__pycache__/__init__.cpython-310.pyc b/megaflow/common/__pycache__/__init__.cpython-310.pyc
new file mode 100644
index 0000000..deca66d
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diff --git a/megaflow/common/__pycache__/utils.cpython-310.pyc b/megaflow/common/__pycache__/utils.cpython-310.pyc
new file mode 100644
index 0000000..94be7f8
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diff --git a/megaflow/dataset/MegaFlow2D.py b/megaflow/dataset/MegaFlow2D.py
index 6278a1c..7d40731 100644
--- a/megaflow/dataset/MegaFlow2D.py
+++ b/megaflow/dataset/MegaFlow2D.py
@@ -4,6 +4,7 @@
 import multiprocessing as mp
 from threading import Thread
 import h5py
+from zipfile import ZipFile
 
 import torch
 from torch import Tensor
@@ -33,7 +34,9 @@ def __init__(self, root, download, transform, pre_transform, split_scheme='mixed
         self.transforms = transform
         self.pre_transform = pre_transform
         if download:
-            self.download()
+            self.download() 
+            # give a warning that the package does not check the integrity of the downloaded data
+            Warning('The package does not check the integrity of the downloaded data. The downloading operation is always executed if the flag download is True. Please disable the download flag if you have already downloaded the data') 
         self.data_list = self.get_data_list
         # self.processed_las_data_dir = os.path.join(self.root, 'processed', 'las')
         # self.processed_has_data_dir = os.path.join(self.root, 'processed', 'has')
@@ -104,12 +107,27 @@ def len(self):
             return 0
         else:
             return len(self.data_list)
+        
+    def _extract_zip(self, path, folder):
+        zips = ["data.zip.00{}".format(i) for i in range(1, 6)]
+        
+        with open(os.path.join(path, "data.zip"), "ab") as f:
+            for zipName in zips:
+                with open(os.path.join(path, zipName), "rb") as z:
+                    f.write(z.read())
+
+                z.close()
+                os.remove(os.path.join(path, zipName))
+
+        with ZipFile(os.path.join(path, "data.zip"), "r") as zipObj:
+            zipObj.extractall(folder)
+        os.remove(os.path.join(path, "data.zip"))
 
     def download(self):
         for i in range(1, 6):
             url = 'https://huggingface.co/datasets/cmudrc/MegaFlow2D/resolve/main/data.zip.00{}'.format(i)
             path = download_url(url, self.root)
-        extract_zip(path, self.root)
+        self._extract_zip(self.root, self.root)
 
     def process(self):
         # Read mesh solution into graph structure
diff --git a/megaflow/dataset/__pycache__/MegaFlow2D.cpython-310.pyc b/megaflow/dataset/__pycache__/MegaFlow2D.cpython-310.pyc
index d01f5fc..4f0b03f 100644
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diff --git a/megaflow/dataset/__pycache__/__init__.cpython-310.pyc b/megaflow/dataset/__pycache__/__init__.cpython-310.pyc
new file mode 100644
index 0000000..3ad36d3
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diff --git a/test.py b/test.py
index 0c489e6..2889ab9 100644
--- a/test.py
+++ b/test.py
@@ -1,4 +1,5 @@
 from megaflow.dataset.MegaFlow2D import MegaFlow2D
 
-# Create a dataset object
-dataset = MegaFlow2D(root='D:/Work/data', download=True)
\ No newline at end of file
+if __name__ == '__main__':
+    # Create a dataset object
+    dataset = MegaFlow2D(root='D:/Work/data', download=True, transform='normalize', pre_transform=None)
\ No newline at end of file