input: Write a function to generate a random password using a predefined set of letters, numbers, and special characters. The function should take no input and return a random password of length 8.
  import random 
    
  def generate_password():
      string = "abcdefghijklmnopqrstuvwxyz01234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ!@#$%^&*()?"
      return "".join(random.sample(string, 8))
  
  assert len(generate_password()) == 8
  assert any(char.isdigit() for char in generate_password())
  assert any(char.islower() for char in generate_password())
  assert any(char.isupper() for char in generate_password())
  assert any(char in "!@#$%^&*()?" for char in generate_password())
output: import random 
    
  def generate_password():
      string = "abcdefghijklmnopqrstuvwxyz01234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ!@#$%^&*()?"
      return "".join(random.sample(string, 8))