<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def default_encoder(obj):
 """ Default encoder for JSON datatypes, which returns UTF-8 encoded json instead of the default bloated backslash u XXXX escaped ASCII strings. """

    if isinstance(obj, bytes):
        return json.dumps(bytes_to_str(obj),
                          ensure_ascii=False).encode("utf-8")
    else:
        return json.dumps(obj, ensure_ascii=False).encode("utf-8")