def dump_attr(ofd, attr, prefix=<NUM_LIT:0>):
dump_hex(ofd, nla_data(attr), nla_len(attr), prefix)<EOL>
https://github.com/thom311/libnl/blob/libnl3_2_25/lib/msg.c#L862.

    Positional arguments:
    ofd -- function to call with arguments similar to `logging.debug`.
    attr -- nlattr class instance.

    Keyword arguments:
    prefix -- additional number of whitespace pairs to prefix each log statement with.