code: def authenticate(self, username, password):
          
  
          r = self._query_('/users/authenticate', 'POST',
                           params={'username': username,
                                   'password': password})
          if r.status_code == 201:
              return r.text.strip('"')
          else:
              raise ValueError('Authentication invalid.')
docs: Authenticates your user and returns an auth token.
  
          :param str username: Hummingbird username.
          :param str password: Hummingbird password.
          :returns: str -- The Auth Token
          :raises: ValueError -- If the Authentication is wrong