<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def nla_for_each_nested(nla, rem):
 """Iterate over a stream of nested attributes. https://github.com/thom311/libnl/blob/libnl3_2_25/include/netlink/attr.h#L274 Positional arguments: nla -- attribute containing the nested attributes (nlattr class instance). rem -- initialized to len, holds bytes currently remaining in stream (c_int). Returns: Generator yielding nlattr instances. """

    pos = nlattr(nla_data(nla))
    rem.value = nla_len(nla)
    while nla_ok(pos, rem):
        yield pos
        pos = nla_next(pos, rem)