def json(content, request=None, response=None, ensure_ascii=False, **kwargs):
    """JSON (Javascript Serialized Object Notation)"""
    if hasattr(content, 'read'):
        return content

    if isinstance(content, tuple) and getattr(content, '_fields', None):
        content = {field: getattr(content, field) for field in content._fields}
    return json_converter.dumps(content, default=_json_converter, ensure_ascii=ensure_ascii, **kwargs).encode('utf8')