Merge pull request scikit-image#3160 from hmaarrfk/maintenance_remove…

…_python_version_checking

Refractor python version checking in __init__.py

skimage/__init__.py

@@ -64,26 +64,8 @@
 
 __version__ = '0.15.dev0'
 
-
-if sys.version_info < (3,):
-    raise ImportError("""
-
-You are running scikit-image on Python 2.
-
-Unfortunately, scikit-image 0.15 and above no longer work on this
-version of Python.  You therefore have two options: either upgrade to
-Python 3, or install an older version of scikit-image using
-
- $ pip install 'scikit-image<0.15'
-
-Please also consider updating `pip` and `setuptools`:
-
- $ pip install pip setuptools --upgrade
-
-Newer versions of these tools avoid installing packages incompatible
-with your version of Python.
-""")
-
+from ._shared.version_requirements import ensure_python_version
+ensure_python_version((3, 5))
 
 # Logic for checking for improper install and importing while in the source
 # tree when package has not been installed inplace.

skimage/_shared/version_requirements.py

@@ -1,9 +1,35 @@
 from distutils.version import LooseVersion
+from platform import python_version
 import functools
 import re
 import sys
 
 
+def ensure_python_version(min_version):
+    if not isinstance(min_version, tuple):
+        min_version = (min_version, )
+    if sys.version_info < min_version:
+        raise ImportError("""
+
+You are running scikit-image on an unsupported version of Python.
+
+Unfortunately, scikit-image 0.15 and above no longer work with your installed
+version of Python (%s).  You therefore have two options: either upgrade to
+Python %s, or install an older version of scikit-image.
+
+For Python 2.7 or Python 3.4, use
+
+ $ pip install 'scikit-image<0.15'
+
+Please also consider updating `pip` and `setuptools`:
+
+ $ pip install pip setuptools --upgrade
+
+Newer versions of these tools avoid installing packages incompatible
+with your version of Python.
+""" % (python_version(), '.'.join([str(v) for v in min_version])))
+
+
 def _check_version(actver, version, cmp_op):
     """
     Check version string of an active module against a required version.