docs: def authenticate(self, username=None, password=None):
          """
          Returns a valid `MojUser` if the authentication is successful
          or None if the credentials were wrong.
          """
          data = api_client.authenticate(username, password)
          if not data:
              return
  
          return User(
              data.get('pk'), data.get('token'), data.get('user_data')
          )