docstring for _default_arguments_from_docstring

IPython/core/completer.py

@@ -666,6 +666,10 b' class IPCompleter(Completer):'
         return matches
 
     def _default_arguments_from_docstring(self,doc):
+        """Parse first line of docstring of the
+        form 'min(iterable[, key=func])\n' to find
+        keyword argument names.
+        """
         doc = doc.lstrip()
         sio = StringIO.StringIO(doc)
         #care only the firstline