["assert remove_Occ(\"hello\",\"l\") == \"heo\"\nassert remove_Occ(\"abcda\",\"a\") == \"bcd\"\nassert remove_Occ(\"PHP\",\"P\") == \"H\"", "assert sort_matrix([[1, 2, 3], [2, 4, 5], [1, 1, 1]])==[[1, 1, 1], [1, 2, 3], [2, 4, 5]]\nassert sort_matrix([[1, 2, 3], [-2, 4, -5], [1, -1, 1]])==[[-2, 4, -5], [1, -1, 1], [1, 2, 3]]\nassert sort_matrix([[5,8,9],[6,4,3],[2,1,4]])==[[2, 1, 4], [6, 4, 3], [5, 8, 9]]"]