def __init__(self, filename=None):
        self.filename = None
        if filename:
            self.load(filename)
def _getProvenance(self, item, user, version=None, resource='item',
                       checkOk=True):
        params = {}
        if version is not None:
            params = {'version': version}
        resp = self.request(
            path='/%s/%s/provenance' % (resource, item['_id']),
            method='GET', user=user, type='application/json', params=params)
        if checkOk:
            self.assertStatusOk(resp)
        return resp