def undefine(self):
if lib.EnvUndefclass(self._env, self._cls) != <NUM_LIT:1>:<EOL><INDENT>raise CLIPSError(self._env)<EOL><DEDENT>self._env = None<EOL>
Undefine the Class.

        Python equivalent of the CLIPS undefclass command.

        The object becomes unusable after this method has been called.