diff --git a/devbin/__init__.py b/devbin/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/devbin/update_version_py.py b/devbin/update_version_py.py
index e182f31..60bd8bb 100755
--- a/devbin/update_version_py.py
+++ b/devbin/update_version_py.py
@@ -9,26 +9,34 @@
 
 VERSIONFILE = "px/version.py"
 
-git_version = (
-    subprocess.check_output(["git", "describe", "--dirty"]).decode("utf-8").strip()
-)
-with tempfile.NamedTemporaryFile(suffix=".py", delete=False) as tmp:
-    tmp.write(b"# NOTE: Auto generated by setup.py, no touchie!\n")
-    tmp.write(b'VERSION = "%s"\n' % bytearray(git_version, "utf_8"))
-
-    # Flushing is required for filecmp.cmp() to work (below)
-    tmp.flush()
-
-    if not os.path.isfile(VERSIONFILE):
-        # No version file found
-        shutil.move(tmp.name, VERSIONFILE)
-    elif not filecmp.cmp(tmp.name, VERSIONFILE):
-        # Version file needs updating
-        shutil.move(tmp.name, VERSIONFILE)
-    else:
-        # VERSIONFILE was already up to date. If we touch it in this
-        # case, it will have its file timestamp updated, which will
-        # force the slow px_integration_test.py tests to get rerun.
-        #
-        # Just clean up our tempfile and be merry.
-        os.remove(tmp.name)
+
+def main():
+    """Update px/version.py with the current git version."""
+    git_version = (
+        subprocess.check_output(["git", "describe", "--dirty"]).decode("utf-8").strip()
+    )
+
+    with tempfile.NamedTemporaryFile(suffix=".py", delete=False) as tmp:
+        tmp.write(b"# NOTE: Auto generated by update_version_py.py, no touchie!\n")
+        tmp.write(b'VERSION = "%s"\n' % bytearray(git_version, "utf_8"))
+
+        # Flushing is required for filecmp.cmp() to work (below)
+        tmp.flush()
+
+        if not os.path.isfile(VERSIONFILE):
+            # No version file found
+            shutil.move(tmp.name, VERSIONFILE)
+        elif not filecmp.cmp(tmp.name, VERSIONFILE):
+            # Version file needs updating
+            shutil.move(tmp.name, VERSIONFILE)
+        else:
+            # VERSIONFILE was already up to date. If we touch it in this
+            # case, it will have its file timestamp updated, which will
+            # force the slow px_integration_test.py tests to get rerun.
+            #
+            # Just clean up our tempfile and be merry.
+            os.remove(tmp.name)
+
+
+if __name__ == "__main__":
+    main()
diff --git a/setup.py b/setup.py
index bddb049..fadbf7f 100755
--- a/setup.py
+++ b/setup.py
@@ -6,6 +6,10 @@
 
 from setuptools import setup
 
+from devbin import update_version_py
+
+update_version_py.main()
+
 git_version = (
     subprocess.check_output(["git", "describe", "--dirty"]).decode("utf-8").strip()
 )