'The ListPipelines operation gets a list of the pipelines
associated with the current AWS account.
:type ascending: string
:param ascending: To list pipelines in chronological order by the date
and time that they were created, enter `True`. To list pipelines in
reverse chronological order, enter `False`.
:type page_token: string
:param page_token: When Elastic Transcoder returns more than one page
of results, use `pageToken` in subsequent `GET` requests to get
each successive page of results.'

def list_pipelines(self, ascending=None, page_token=None):

    uri = '/2012-09-25/pipelines'.format()
    params = {}
    if (ascending is not None):
        params['Ascending'] = ascending
    if (page_token is not None):
        params['PageToken'] = page_token
    return self.make_request('GET', uri, expected_status=200, params=params)
