diff --git a/alembic_viz/alembic_viz.py b/alembic_viz/alembic_viz.py
index 90e1438..5a39ee7 100644
--- a/alembic_viz/alembic_viz.py
+++ b/alembic_viz/alembic_viz.py
@@ -4,8 +4,8 @@
 from alembic.util import CommandError
 import click
 
-from utils import get_revisions
-from utils import generate_revision_graph
+from .utils import get_revisions
+from .utils import generate_revision_graph
 
 VALID_OUTPUT_FORMATS = ['png', 'svg', 'pdf']
 
diff --git a/alembic_viz/utils.py b/alembic_viz/utils.py
index 8470bbf..fc9f827 100644
--- a/alembic_viz/utils.py
+++ b/alembic_viz/utils.py
@@ -26,7 +26,7 @@ def generate_revision_graph(revisions, format):
         if revision.down_revision is None:
             dot.edge('base', revision.revision)
             continue
-        if isinstance(revision.down_revision, basestring):
+        if isinstance(revision.down_revision, str):
             dot.edge(revision.down_revision, revision.revision)
             continue
         for down_revision in revision.down_revision:
diff --git a/requirements.txt b/requirements.txt
index 886ab25..b050695 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -4,10 +4,10 @@
 #
 #    pip-compile --output-file requirements.txt requirements.in
 #
-alembic==0.8.8
-click==6.6
-graphviz==0.5.1
-Mako==1.0.5               # via alembic
-MarkupSafe==0.23          # via mako
-python-editor==1.0.1      # via alembic
-SQLAlchemy==1.1.3         # via alembic
+alembic==1.3.0
+click==7.0
+graphviz==0.13
+Mako==1.1.0               # via alembic
+MarkupSafe==1.1.1          # via mako
+python-editor==1.0.4      # via alembic
+SQLAlchemy==1.3.10         # via alembic