def assert_required_parameters(self, parameters, operation):
    """ Checks the given parameters to make sure that they can be used to
    interact with Google Compute Engine.

    Args:
      parameters: A dict that maps the name of each credential to be used in GCE
        with the value we should use.
      operation: A BaseAgent.OPERATION that indicates if we wish to add or
        delete instances. Unused here, as all operations require the same
        credentials.
    Raises:
      AgentConfigurationException: If any of the required credentials are not
        present, or if the client_secrets parameter refers to a file that is not
        present on the local filesystem.
    """
    # Make sure the user has set each parameter.
    for param in self.REQUIRED_CREDENTIALS:
      if param not in parameters:
        raise AgentConfigurationException('The required parameter, {0}, was' \
          ' not specified.'.format(param))

    # Next, make sure that the oauth2 file exists
    if not os.path.exists(self.OAUTH2_STORAGE_LOCATION):
      raise AgentConfigurationException('Could not find your signed OAuth2' \
        'file at {0}'.format(self.OAUTH2_STORAGE_LOCATION))
dataset/ETHPy150Open AppScale/appscale/InfrastructureManager/agents/gce_agent.py/GCEAgent.assert_required_parameters/original