def add_payload(self, payload):
if self._payload is None:<EOL><INDENT>self.decode_payload()<EOL><DEDENT>if isinstance(payload, ElementClass):<EOL><INDENT>self._payload.append(XMLPayload(payload))<EOL><DEDENT>elif isinstance(payload, StanzaPayload):<EOL><INDENT>self._payload.append(payload)<EOL><DEDENT>else:<EOL><INDENT>raise TypeError("<STR_LIT>")<EOL><DEDENT>self._dirty = True<EOL>
Add new the stanza payload.

        Marks the stanza dirty.

        :Parameters:
            - `payload`: XML element or stanza payload object to add
        :Types:
            - `payload`: :etree:`ElementTree.Element` or `StanzaPayload`