Merge pull request #87 from marcelm/patch-1

Demonstrate python_requires usage

setup.py

@@ -105,6 +105,8 @@
 
         # Specify the Python versions you support here. In particular, ensure
         # that you indicate whether you support Python 2, Python 3 or both.
+        # These classifiers are *not* checked by 'pip install'. See instead
+        # 'python_requires' below.
         'Programming Language :: Python :: 2',
         'Programming Language :: Python :: 2.7',
         'Programming Language :: Python :: 3',
@@ -131,6 +133,13 @@
     #
     packages=find_packages(exclude=['contrib', 'docs', 'tests']),  # Required
 
+    # Specify which Python versions you support. In contrast to the
+    # 'Programming Language' classifiers above, 'pip install' will check this
+    # and refuse to install the project if the version does not match. If you
+    # do not support Python 2, you can simplify this to '>=3.5' or similar, see
+    # https://packaging.python.org/guides/distributing-packages-using-setuptools/#python-requires
+    python_requires='>=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, <4',
+
     # This field lists other packages that your project depends on to run.
     # Any package you put here will be installed by pip when your project is
     # installed, so they must be valid existing projects.