def assertAllNan(self, a):
is_nan = np.isnan(self._GetNdArray(a))<EOL>all_true = np.ones_like(is_nan, dtype=np.bool)<EOL>self.assertAllEqual(all_true, is_nan)<EOL>
Assert that every entry in a `Tensor` is NaN.

        Args:
          a: A `Tensor` whose entries must be verified as NaN.