def lookup_default(self, name):
if self.default_map is not None:<EOL><INDENT>rv = self.default_map.get(name)<EOL>if callable(rv):<EOL><INDENT>rv = rv()<EOL><DEDENT>return rv<EOL><DEDENT>
Looks up the default for a parameter name.  This by default
        looks into the :attr:`default_map` if available.