def login(self, username=None, password=None):
        """ Before doing any remote operation, the user has to login to the GMQL serivice.
        This can be done in the two following ways:

            * Guest mode: the user has no credentials and uses the system only as a temporary guest
            * Authenticated mode: the users has credentials and a stable remote account

        If neither username and password are specified, the user enters the system as a guest.
        If both are specified and they correspond to an existent user, the user enters as an
        authenticated user

        :param username: (optional)
        :param password: (optional)
        :return: None
        """
        if (username is None) and (password is None):
            auth_token = self.__login_guest()
        elif (username is not None) and (password is not None):
            auth_token, fullName = self.__login_credentials(username, password)
            self.logger.info("You are logged as {}".format(fullName))
        else:
            raise ValueError("you have to specify both username and password or nothing")

        if auth_token is not None:
            self.auth_token = auth_token
        else:
            raise ConnectionError("Impossible to retrieve the authentication token")
def login ( self , username = None , password = None ) : if ( username is None ) and ( password is None ) : auth_token = self . __login_guest ( ) elif ( username is not None ) and ( password is not None ) : auth_token , fullName = self . __login_credentials ( username , password ) self . logger . info ( "You are logged as {}" . format ( fullName ) ) else : raise ValueError ( "you have to specify both username and password or nothing" ) if auth_token is not None : self . auth_token = auth_token else : raise ConnectionError ( "Impossible to retrieve the authentication token" )
Before doing any remote operation, the user has to login to the GMQL serivice.
        This can be done in the two following ways:

            * Guest mode: the user has no credentials and uses the system only as a temporary guest
            * Authenticated mode: the users has credentials and a stable remote account

        If neither username and password are specified, the user enters the system as a guest.
        If both are specified and they correspond to an existent user, the user enters as an
        authenticated user

        :param username: (optional)
        :param password: (optional)
        :return: None