@classmethod
def serialize_item(cls, item, args=None):
    """
        Serialize a query that stored in ``item`` tuple like: (key, value)
        """
    fields = getattr(cls, 'fields', None)
    if fields and isinstance(fields, dict):
        if item[0] in fields:
            return fields[item(0)].serialize(item[1], params=args)
    return {item[0]: item[1]}
