@typecheck_method(cond=IR, cnsq=IR, altr=IR)
def copy(self, cond, cnsq, altr):
    new_instance = self.__class__
    return new_instance(cond, cnsq, altr)
@typecheck_method(cond=IR, cnsq=IR, altr=IR)
def copy(self, cond, cnsq, altr):
    new_instance = self.__class__
    return new_instance(cond, cnsq, altr)