Single sourcing version

Pattern from: https://packaging.python.org/guides/single-sourcing-package-version/

setup.py

 #!/usr/bin/env python
 import os
+import io
+import re
 import shutil
 import sys
 from setuptools import setup, find_packages
 
 
+def read(*names, **kwargs):
+    with io.open(
+        os.path.join(os.path.dirname(__file__), *names),
+        encoding=kwargs.get("encoding", "utf8")
+    ) as fp:
+        return fp.read()
+
+def find_version(*file_paths):
+    version_file = read(*file_paths)
+    version_match = re.search(r"^__version__ = ['\"]([^'\"]*)['\"]",
+                              version_file, re.M)
+    if version_match:
+        return version_match.group(1)
+    raise RuntimeError("Unable to find version string.")
+
 readme = open('README.rst').read()
 
-VERSION = '0.1.9'
+VERSION = find_version('torchvision', '__init__.py')
 
 requirements = [
     'numpy',

torchvision/__init__.py

@@ -3,6 +3,7 @@ from torchvision import datasets
 from torchvision import transforms
 from torchvision import utils
 
+__version__ = '0.1.9'
 
 _image_backend = 'PIL'