def METHOD_NAME(self):
    # visit the types that are actually used
    jsons = self._jsons
    self._jsons = []
    for typ in self._used_types:
        typ.visit(self)
    # generate C
    # TODO can generate awfully long lines
    jsons.extend(self._jsons)
    name = c_name(prefix, protect=False) + 'qmp_schema_json'
    self.decl = mcgen('''