input: Write a python function to generate a random password of length 16 that includes lowercase, uppercase, digits, and punctuation.
  assert len(generate_password()) == 16
  assert any(c.islower() for c in generate_password())
  assert any(c.isupper() for c in generate_password())
  assert any(c.isdigit() for c in generate_password())
  assert any(c in string.punctuation for c in generate_password())
output: import string
  import random
  
  def generate_password(length=16):
      characters = string.ascii_letters + string.digits + string.punctuation
      while True:
          password = ''.join(random.choice(characters) for i in range(length))
          if (any(c.islower() for c in password) and 
              any(c.isupper() for c in password) and 
              any(c.isdigit() for c in password) and 
              any(c in string.punctuation for c in password)):
              return password