newforms: Added docstring to Widget.build_attrs()

git-svn-id: http://code.djangoproject.com/svn/django/trunk@4134 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/newforms/widgets.py

@@ -30,6 +30,7 @@ class Widget(object):
         raise NotImplementedError
 
     def build_attrs(self, extra_attrs=None, **kwargs):
+        "Helper function for building an attribute dictionary."
         attrs = dict(self.attrs, **kwargs)
         if extra_attrs:
             attrs.update(extra_attrs)