input: Write a function to print the multiplication table of a given integer n.
  def f(n):
      for i in range(1, 11):
          print("{} * {} = {}".format(n, i, n*i))
  assert f(5)==None
  assert f(10)==None
  assert f(1)==None
output: def f(n):
      for i in range(1, 11):
          print("{} * {} = {}".format(n, i, n*i))