input: Write a python function to generate a random password of a given length.
  assert len(generate_random_password(6)) == 6
  assert len(generate_random_password(10)) == 10
  assert len(generate_random_password(15)) == 15
output: import random
  import string
  
  def generate_random_password(length):
      characters = string.ascii_letters + string.digits + string.punctuation
      password = ''.join(random.choice(characters) for i in range(length))
      return password