Could someone please help me answer this in Python? is_diagonal: This Boolean function takes a nonempty numerical list of lists (hereafter referred to as a matrix) as its sole argument and returns True if the argument is a diagonal matrix, False otherwise. In diagonal matrices, all off-diagonal elements are zero. For example the following matrix would be diagonal. [[1, 0], [0, 1], [0, 0], [0, 0]] The image below is an example of diagonal matrices.

and 0 0 0 0 2 1