@classmethod<EOL><INDENT>def attributes(cls):<DEDENT>
for k in dir(cls):<EOL><INDENT>v = getattr(cls, k)<EOL>if isinstance(v, Attribute):<EOL><INDENT>yield k,v<EOL><DEDENT><DEDENT>
yields tuples for all attributes defined on this handler

tuple yielded:
    name (str), attribute (Attribute)