Driver function
mat = [ [ 4 , 0 , 0 , 0 ] , [ 0 , 7 , 0 , 0 ] , [ 0 , 0 , 5 , 0 ] , [ 0 , 0 , 0 , 1 ] ] NEW_LINE if ( isDiagonalMatrix ( mat ) ) : NEW_LINE INDENT print ( " Yes " ) NEW_LINE DEDENT else : NEW_LINE INDENT print ( " No " ) NEW_LINE DEDENT