'Validates a pipeline and initiates processing. If the pipeline
does not pass validation, activation fails.
Call this action to start processing pipeline tasks of a
pipeline you\'ve created using the CreatePipeline and
PutPipelineDefinition actions. A pipeline cannot be modified
after it has been successfully activated.
:type pipeline_id: string
:param pipeline_id: The identifier of the pipeline to activate.'

def activate_pipeline(self, pipeline_id):

    params = {'pipelineId': pipeline_id}
    return self.make_request(action='ActivatePipeline', body=json.dumps(params))
