def test_len_signature(self):
    """Signatures of all sizes should give correct length when asked."""
    x1 = np.array([1, 2, 3])
    x2 = np.array([10, 20, 30])
    inputs0 = ()
    inputs1 = x1  # NOT in a tuple
    inputs2 = (x1, x2)

    sig0 = shapes.signature(inputs0)
    sig1 = shapes.signature(inputs1)
    sig2 = shapes.signature(inputs2)

    # pylint: disable=g-generic-assert
    self.assertEqual(len(sig0), 0)
    self.assertEqual(len(sig1), 1)
    self.assertEqual(len(sig2), 2)
    # pylint: enable=g-generic-assert
Signatures of all sizes should give correct length when asked.
trax/shapes_test.py