Automatic Reshaping

import numpy as np

a = np.arange(80)

a.shape = 2, 5, -1

a

array([[[ 0,  1,  2,  3,  4,  5,  6,  7],
        [ 8,  9, 10, 11, 12, 13, 14, 15],
        [16, 17, 18, 19, 20, 21, 22, 23],
        [24, 25, 26, 27, 28, 29, 30, 31],
        [32, 33, 34, 35, 36, 37, 38, 39]],

       [[40, 41, 42, 43, 44, 45, 46, 47],
        [48, 49, 50, 51, 52, 53, 54, 55],
        [56, 57, 58, 59, 60, 61, 62, 63],
        [64, 65, 66, 67, 68, 69, 70, 71],
        [72, 73, 74, 75, 76, 77, 78, 79]]])

a.shape

(2, 5, 8)

# Here 8 is automatically assumed (as we said -1)