text: class User:
      """
      Class that generates new instances of users
      """
  
      user_list = []
      def save_user(self):
          '''
          save_user method saves contact objects into user_list
          '''
          User.user_list.append(self)
  
      def delete_user(self):
          '''
          delete_user method deletes a saved user from the user_list
          '''
          User.user_list.remove(self)   
   
  
      def __init__(self, first_name, last_name, user_name, password):
          '''
          init__helps us to define our users' properties.
          Args:
              first_name: New contact first name.
              last_name: New contact last name.
              user_name: New user's login username.
              password: New user's login password   
          '''
  
          self.first_name = first_name
          self.last_name = last_name
          self.user_name = user_name
          self.password = password
      @classmethod
      def find_by_user_name(cls,user_name):   
          '''
          Method that takes in a number and returns a contact that matches that number.
          Args:
          user_name:user_name to search for
          Returns:
          Users of person that matches the user_name.
          '''
          for user in cls.user_list:
              if user.user_name == user_name:
                  return user
      @classmethod
      def user_exist(cls,user_name):
          '''
          Method that checks if a user exists from the user list.
          
          Args:
          user_name: User_name to search if it exists 
          Returns:
          Boolean: True or false depending if the user exists
          '''
          for user in cls.user_list:
              if user.user_name == user_name:
                  return True
  
          return False