human
Here's a good function header given the following:
I wrote the below code

    d = node.run_script('service_running', 'flocker-container-agent')
    def not_existing(failure):
        failure.trap(ProcessTerminated)
        return False
    d.addCallbacks((lambda result: True), not_existing)
    return d

What's a good function header?
assistant
#Here's a good function header.

def is_container_agent_running(node):