Fix None docstring when running in -OO mode (#414)

Author: jcharlong

CHANGELOG.md

@@ -15,6 +15,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - Include docs in source distributions as well the whole tests folder,
   ensuring `conftest.py` is present, fixes [#364](https://github.com/PyFilesystem/pyfilesystem2/issues/364).
 - Stop patching copy with Python 3.8+ because it already uses sendfile.
+- Fixed crash when CPython's -OO flag is used
 
 ## [2.4.11] - 2019-09-07
 

CONTRIBUTORS.md

@@ -6,6 +6,7 @@ Many thanks to the following developers for contributing to this project:
 - [Diego Argueta](https://github.com/dargueta)
 - [Geoff Jukes](https://github.com/geoffjukes)
 - [Giampaolo](https://github.com/gpcimino)
+- [Justin Charlong](https://github.com/jcharlong)
 - [Louis Sautier](https://github.com/sbraz)
 - [Martin Larralde](https://github.com/althonos)
 - [Will McGugan](https://github.com/willmcgugan)

fs/base.py

@@ -84,7 +84,7 @@ def _method(*args, **kwargs):
 """.format(
         method.__name__
     )
-    if hasattr(_method, "__doc__"):
+    if getattr(_method, "__doc__", None) is not None:
         _method.__doc__ += deprecated_msg
 
     return _method