Could someone please help me solve this in Python? Brief explanation of the code comments would be greatly appreciated.

indices_second_biggest: This function returns a list containing the indices of the second largest value in its sole argument, a nonempty matrix (list of lists), i.e. [row index, col index]. If the largest value occurs more than once, it counts as the second largest also. If there is only one element in the matrix, return [0, 0].