diff --git a/rig/utils/docstrings.py b/rig/utils/docstrings.py
index <HASH>..<HASH> 100644
--- a/rig/utils/docstrings.py
+++ b/rig/utils/docstrings.py
@@ -36,7 +36,10 @@ def add_int_enums_to_docstring(enum):
         b = 1
         <BLANKLINE>
     """
-    if enum.__doc__ is None:
+    # The enum34 library (used for compatibility with Python < v3.4) rather
+    # oddly set its docstring to None rather than some senible but empty
+    # default...
+    if enum.__doc__ is None:  # pragma: nocover
         enum.__doc__ = ""
 
     enum.__doc__ += ("\n\n"
Fix coverage of docstrings utility module.

The enum<I> library sets the docstring of enums to None by default while native
Python>=<I> enums have a default docstring. As such some of the code to handle
this situation becomes dead in Python <I> onwards when the enum<I> library is
not used. This commit thus disables coverage checking for the code since it
will not get meaningfully hit in Python <I> onwards.