def emit_stanza(self, element):
if not self._head_emitted:<EOL><INDENT>raise RuntimeError("<STR_LIT>")<EOL><DEDENT>string = self._emit_element(element, level = <NUM_LIT:1>,<EOL>declared_prefixes = self._root_prefixes)<EOL>return remove_evil_characters(string)<EOL>
Serialize a stanza.

        Must be called after `emit_head`.

        :Parameters:
            - `element`: the element to serialize
        :Types:
            - `element`: :etree:`ElementTree.Element`

        :Return: serialized element
        :Returntype: `unicode`