'Return a list of backends that can fulfill query requirements.'

def backend_passes(self, backend_state, filter_properties):

    try:
        query = filter_properties['scheduler_hints']['query']
    except KeyError:
        query = None
    if (not query):
        return True
    result = self._process_filter(jsonutils.loads(query), backend_state)
    if isinstance(result, list):
        result = any(result)
    if result:
        return True
    return False
