input: Write a function to format a two-dimensional array as a table and print it. If the array is empty, print nothing.
  assert printTable([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
  assert printTable([[1, 2], [3, 4]])
  assert printTable([[10, 20], [30, 40]])
  assert printTable([[1], [2]])
  assert printTable([])==None
output: def printTable(arr):
      if not arr:
          return
      col_widths = [max(len(str(item)) for item in row) for row in zip(*arr)]
      for row in arr:
          print(" ".join(str(item).rjust(col_widths[i]) for i, item in enumerate(row)))