input: Write a python function to check if a number is divisible by 7.
  assert is_divisible_by_7(92) == False
  assert is_divisible_by_7(49) == True
  assert is_divisible_by_7(14) == True
  assert is_divisible_by_7(100) == False
output: def is_divisible_by_7(n):
      return n % 7 == 0