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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def use(cls, ec):
 """ use will duplicate a new Model class and bind ec ec is Engine name or Sesstion object """

        
        if isinstance(ec, (str, unicode)):
            m = get_model(cls._alias, ec, signal=False)
        else:
            m = cls._use(ec)
        return m