The axis or axes along which to perform the reduction.
axis=(), will compute over all elements into a
scalar array with shape
axis is int, a reduction is performed on a particular axis.
axis is a 2-tuple, it specifies the axes that hold 2-D matrices,
and the matrix norms of these matrices are computed.
If this is set to
True, the reduced axis is left in the result as dimension with size one.
Order of the norm. Currently ord=1 and ord=2 is supported.