def nest(self, verb):
if not isinstance(verb, TwiML) and not isinstance(verb, str):<EOL><INDENT>raise TwiMLException('<STR_LIT>')<EOL><DEDENT>self.verbs.append(verb)<EOL>return verb<EOL>
Add a TwiML doc. Unlike `append()`, this returns the created verb.

:param verb: TwiML Document

:returns: the TwiML verb