Python/Numpy:将N4xN3xN2xN1 4D数组重新排列为(N4.N2)x(N3.N1) 2D数组

For example, if:

例如,如果:

a = numpy.array([[[[1,2],[3,4]],[[5,6],[7,8]]],[[[11,12],[13,14]],[[15,16],[17,18]]]])
a = numpy.array([[[