Expand docstring to explain return value.

maxalbert · maxalbert · commit 27cbd348c97a · 2016-01-13T11:54:17.000Z
diff --git a/lib/matplotlib/testing/decorators.py b/lib/matplotlib/testing/decorators.py
@@ -364,7 +364,9 @@ def _image_directories(func):
 
         import imp
         def find_dotted_module(module_name, path=None):
-            """A version of imp which can handle dots in the module name"""
+            """A version of imp which can handle dots in the module name.
+               As for imp.find_module(), the return value is a 3-element
+               tuple (file, pathname, description)."""
             res = None
             for sub_mod in module_name.split('.'):
                 try:
