Merge pull request #98 from cloudblue/pip-v20-fix

Fix for pip v20.X

Author: marcserrat

setup.py

@@ -7,12 +7,19 @@
 from os.path import abspath, dirname, exists, join
 from setuptools import find_packages, setup
 
-try:  # for pip >= 10
-    # noinspection PyProtectedMember,PyPackageRequirements
+try:
+    # pip >=20
+    from pip._internal.network.session import PipSession
     from pip._internal.req import parse_requirements
-except ImportError:  # for pip <= 9.0.3
-    # noinspection PyPackageRequirements,PyUnresolvedReferences
-    from pip.req import parse_requirements
+except ImportError:
+    try:
+        # 10.0.0 <= pip <= 19.3.1
+        from pip._internal.download import PipSession
+        from pip._internal.req import parse_requirements
+    except ImportError:
+        # pip <= 9.0.3
+        from pip.download import PipSession
+        from pip.req import parse_requirements
 
 # noinspection PyTypeChecker
 install_reqs = parse_requirements(