input: Write a python function to generate a multiplication table with given rows and columns.
  assert multiplicationTable(3, 3) == [[1, 2, 3], [2, 4, 6], [3, 6, 9]]
  assert multiplicationTable(2, 5) == [[1, 2, 3, 4, 5], [2, 4, 6, 8, 10]]
  assert multiplicationTable(4, 4) == [[1, 2, 3, 4], [2, 4, 6, 8], [3, 6, 9, 12], [4, 8, 12, 16]]
output: def multiplicationTable(rows, cols):
      return [[(i + 1) * (j + 1) for j in range(cols)] for i in range(rows)]