def _update_data(self):
func = self.owner.formula.func<EOL>codeobj = func.__code__<EOL>name = func.__name__  <EOL>namespace_impl = self.owner._namespace_impl.get_updated()<EOL>namespace = namespace_impl.interfaces<EOL>selfnode = get_node(self.owner, None, None)<EOL>for name in self.owner.formula.srcnames:<EOL><INDENT>if name in namespace_impl and isinstance(<EOL>namespace_impl[name], ReferenceImpl<EOL>):<EOL><INDENT>refnode = get_node(namespace_impl[name], None, None)<EOL>self.owner.model.lexdep.add_path([selfnode, refnode])<EOL><DEDENT><DEDENT>closure = func.__closure__  <EOL>if closure is not None:  <EOL><INDENT>closure = create_closure(self.owner.interface)<EOL><DEDENT>self.altfunc = FunctionType(<EOL>codeobj, namespace, name=name, closure=closure<EOL>)<EOL>
Update altfunc