input: Write a python function to generate a random password containing at least one uppercase letter, one lowercase letter, and one digit.
  assert len(get_password()) == 8
  assert any(x.isupper() for x in get_password())
  assert any(x.islower() for x in get_password())
  assert any(x.isdigit() for x in get_password())
output: import random
  import string
  
  def get_password():
      characters = list(string.ascii_letters + string.digits)
      password = [
          random.choice(string.ascii_uppercase),
          random.choice(string.ascii_lowercase),
          random.choice(string.digits),
      ]
      password += random.choices(characters, k=5)
      random.shuffle(password)
      return ''.join(password)