Set credentials for Application authentication.
        Important Note: Do not use Application auth on any end-user device.
        Application auth provides read-access to all Users who have
        authorized an Application. Use on a secure application server only.

        Args:
          api_token (str): Token issued to your Application through the Gem
            Developer Console.
          admin_token (str): Token issued to run an instance of your App
            THIS IS A SECRET. TREAT IT LIKE A SECRET.
          override (boolean): Replace existing Application credentials.
          fetch (boolean): Return the authenticated Application.

        Returns:
          An Application object if `fetch` is True.

def authenticate_application(self, api_token, admin_token,
                                 override=False, fetch=True):
        """Set credentials for Application authentication.
        Important Note: Do not use Application auth on any end-user device.
        Application auth provides read-access to all Users who have
        authorized an Application. Use on a secure application server only.

        Args:
          api_token (str): Token issued to your Application through the Gem
            Developer Console.
          admin_token (str): Token issued to run an instance of your App
            THIS IS A SECRET. TREAT IT LIKE A SECRET.
          override (boolean): Replace existing Application credentials.
          fetch (boolean): Return the authenticated Application.

        Returns:
          An Application object if `fetch` is True.
        """
        if (self.context.has_auth_params('Gem-Application') and not override):
            raise OverrideError('Gem-Application')

        if (not api_token or not admin_token or
            not self.context.authorize('Gem-Application',
                                       api_token=api_token,
                                       admin_token=admin_token)):
            raise AuthUsageError(self.context, 'Gem-Application')

        return self.application if fetch else True