input: Write a function to generate a random password consisting of 8 characters. The password should include a combination of uppercase and lowercase letters, as well as digits. If the function is called without any input, it will return a string of 8 random characters.
  assert generate_password()!=generate_password()
  assert len(generate_password())==8
  assert any(c.islower() for c in generate_password())==True
  assert any(c.isupper() for c in generate_password())==True
  assert any(c.isdigit() for c in generate_password())==True
output: import random
  import string
  
  def generate_password():
      characters = string.ascii_letters + string.digits
      return ''.join(random.choice(characters) for _ in range(8))