'Returns the definition of the specified pipeline. You can call
GetPipelineDefinition to retrieve the pipeline definition you
provided using PutPipelineDefinition.
:type pipeline_id: string
:param pipeline_id: The identifier of the pipeline.
:type version: string
:param version: The version of the pipeline definition to retrieve.
This parameter accepts the values `latest` (default) and `active`.
Where `latest` indicates the last definition saved to the pipeline
and `active` indicates the last definition of the pipeline that was
activated.'

def get_pipeline_definition(self, pipeline_id, version=None):

    params = {'pipelineId': pipeline_id}
    if (version is not None):
        params['version'] = version
    return self.make_request(action='GetPipelineDefinition', body=json.dumps(params))
