How to use the gbdxtools.simpleworkflows.WorkflowError function in gbdxtools

def test_workflow_task_ids_with_unstarted_workflow(self):
        workflow = self.gbdx.Workflow([])

        with self.assertRaises(WorkflowError):
            task_ids = workflow.task_ids

def test_create_simpleworkflow(self):
        aoptask = self.gbdx.Task("AOP_Strip_Processor", data='dummy', enable_acomp=False, enable_pansharpen=False)
        s3task = self.gbdx.Task("StageDataToS3", data=aoptask.get_output('log'), destination='dummydestination')
        workflow = self.gbdx.Workflow([s3task, aoptask])

        assert isinstance(workflow, Workflow)
        assert workflow.id is None
        assert workflow.name is not None

        try:
            workflow.status
        except WorkflowError as e:
            pass
        else:
            raise Exception('failed test')

        assert not workflow.complete

(list): tasks with their stdout
        
        Example:
            >>> workflow.stdout
            [
                {
                    "id": "4488895771403082552",
                    "taskType": "AOP_Strip_Processor",
                    "name": "Task1",
                    "stdout": "............"
                }
            ]

        '''
        if not self.id:
            raise WorkflowError('Workflow is not running.  Cannot get stdout.')
        if self.batch_values:
            raise NotImplementedError("Query Each Workflow Id within the Batch Workflow for stdout.")

        wf = self.workflow.get(self.id)

        stdout_list = []
        for task in wf['tasks']:
            stdout_list.append(
                {
                    'id': task['id'],
                    'taskType': task['taskType'],
                    'name': task['name'],
                    'stdout': self.workflow.get_stdout(self.id, task['id'])
                }
            )

def status(self):
        if not self.id:
            raise WorkflowError('Workflow is not running.  Cannot check status.')

        if self.batch_values:
            status = self.workflow.batch_workflow_status(self.id)
        else:
            status = self.workflow.status(self.id)

        return status

def cancel(self):
        '''
        Cancel a running workflow.

        Args:
            None

        Returns:
            None
        '''
        if not self.id:
            raise WorkflowError('Workflow is not running.  Cannot cancel.')

        if self.batch_values:
            self.workflow.batch_workflow_cancel(self.id)
        else:
            self.workflow.cancel(self.id)

def generate_workflow_description(self):
        '''
        Generate workflow json for launching the workflow against the gbdx api

        Args:
            None

        Returns:
            json string
        '''
        if not self.tasks:
            raise WorkflowError('Workflow contains no tasks, and cannot be executed.')

        self.definition = self.workflow_skeleton()

        if self.batch_values:
            self.definition["batch_values"] = self.batch_values

        all_input_port_values = [t.inputs.__getattribute__(input_port_name).value for t in self.tasks for
                                 input_port_name in t.inputs._portnames]
        for task in self.tasks:
            # only include multiplex output ports in this task if other tasks refer to them in their inputs.
            # skip this if there is only one task in the workflow
            # 1. find the multplex output port_names in this task
            # 2. see if they are referred to in any other tasks inputs
            # 3. If not, exclude them from the workflow_def
            output_multiplex_ports_to_exclude = []
            if len(self.tasks) > 1:

def task_ids(self):
        '''
        Get the task IDs of a running workflow

        Args:
            None

        Returns:
            List of task IDs
        '''
        if not self.id:
            raise WorkflowError('Workflow is not running.  Cannot get task IDs.')

        if self.batch_values:
            raise NotImplementedError("Query Each Workflow Id within the Batch Workflow for task IDs.")

        wf = self.workflow.get(self.id)

        return [task['id'] for task in wf['tasks']]

def events(self):
        if not self.id:
            raise WorkflowError('Workflow is not running.  Cannot check status.')
        if self.batch_values:
            raise NotImplementedError("Query Each Workflow Id within the Batch Workflow for Events")
        return self.workflow.events(self.id)

Example:
            >>> workflow.stderr
            [
                {
                    "id": "4488895771403082552",
                    "taskType": "AOP_Strip_Processor",
                    "name": "Task1",
                    "stderr": "............"
                }
            ]

        '''

        if not self.id:
            raise WorkflowError('Workflow is not running.  Cannot get stderr.')
        if self.batch_values:
            raise NotImplementedError("Query Each Workflow Id within the Batch Workflow for stderr.")

        wf = self.workflow.get(self.id)

        stderr_list = []
        for task in wf['tasks']:
            stderr_list.append(
                {
                    'id': task['id'],
                    'taskType': task['taskType'],
                    'name': task['name'],
                    'stderr': self.workflow.get_stderr(self.id, task['id'])
                }
            )