How to use the pyflow.demo.helloWorld.helloWorld.HelloWorkflow function in pyflow

class HelloWorkflow(WorkflowRunner) :

    # a workflow is defined by overloading the WorkflowRunner.workflow() method:
    #
    def workflow(self) :

        #
        # The output for this task will be written to the file helloWorld.out.txt
        #
        self.addTask("easy_task1", "echo 'Hello World!' > helloWorld.out.txt")



# Instantiate the workflow
#
wflow = HelloWorkflow()

# Run the worklow:
#
retval = wflow.run()

# done!
sys.exit(retval)