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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 identity_factor(self):
 """ Returns the identity factor. Def: The identity factor of a factor has the same scope and cardinality as the original factor, but the values for all the assignments is 1. When the identity factor is multiplied with the factor it returns the factor itself. Returns ------- DiscreteFactor: The identity factor. Examples -------- ['x1', 'x2', 'x3'] array([[[ 1., 1.], [ 1., 1.], [ 1., 1.]], [[ 1., 1.], [ 1., 1.], [ 1., 1.]]]) """

        return DiscreteFactor(self.variables, self.cardinality, np.ones(self.values.size))