def is_Identity(self):
        """
        Returns True if the Permutation is an identity permutation.

        Examples
        ========

        >>> p = Permutation([])
        >>> p.is_Identity
        True
        >>> p = Permutation([[0], [1], [2]])
        >>> p.is_Identity
        True
        >>> p = Permutation([0, 1, 2])
        >>> p.is_Identity
        True
        >>> p = Permutation([0, 2, 1])
        >>> p.is_Identity
        False

        See Also
        ========

        order

        """
        af = self.array_form
        return not af or all(i == af[i] for i in range(self.size))