description: Functional interface to the Concatenate layer.
>>> x = np.arange(20).reshape(2, 2, 5)
>>> print(x)
[[[ 0 1 2 3 4]
[ 5 6 7 8 9]]
[[10 11 12 13 14]
[15 16 17 18 19]]]
>>> y = np.arange(20, 30).reshape(2, 1, 5)
>>> print(y)
[[[20 21 22 23 24]]
[[25 26 27 28 29]]]
>>> tf.keras.layers.concatenate([x, y],
... axis=1)
<tf.Tensor: shape=(2, 3, 5), dtype=int64, numpy=
array([[[ 0, 1, 2, 3, 4],
[ 5, 6, 7, 8, 9],
[20, 21, 22, 23, 24]],
[[10, 11, 12, 13, 14],
[15, 16, 17, 18, 19],
[25, 26, 27, 28, 29]]])>