def _create_poller(operation):
    """
    Creates an operation poller from the passed in operation.

    :param operation: A dict representing a GCE operation resource.

    :returns: An :class:`OperationPoller` provider that can poll the status of
        the operation.
    """
    try:
        operation_name = operation['name']
    except KeyError:
        raise MalformedOperation(
            u"Failed to parse operation, could not find key "
            u"name in: {}".format(operation)
        )
    if 'zone' in operation:
        zone_url_parts = unicode(operation['zone']).split('/')
        try:
            project = zone_url_parts[-3]
            zone = zone_url_parts[-1]
        except IndexError:
            raise MalformedOperation(
                "'zone' key of operation had unexpected form: {}.\n"
                "Expected '(.*/)?<project>/zones/<zone>'.\n"
                "Full operation: {}.".format(operation['zone'], operation))
        return ZoneOperationPoller(
            zone=unicode(zone),
            project=unicode(project),
            operation_name=unicode(operation_name)
        )
    else:
        try:
            project = unicode(operation['selfLink']).split('/')[-4]
        except KeyError:
            raise MalformedOperation(
                u"Failed to parse global operation, could not find key "
                u"selfLink in: {}".format(operation)
            )
        except __HOLE__:
            raise MalformedOperation(
                "'selfLink' key of operation had unexpected form: {}.\n"
                "Expected '(.*/)?<project>/global/operations/<name>'.\n"
                "Full operation: {}.".format(operation['selfLink'], operation))
        return GlobalOperationPoller(
            project=unicode(project),
            operation_name=unicode(operation_name)
        )
dataset/ETHPy150Open ClusterHQ/flocker/flocker/node/agents/gce.py/_create_poller