code: def walk_json_dict(coll):
    
    if isinstance(coll, dict):
      return dict((k, walk_json_dict(v)) for (k, v) in iter(coll.items()))
    elif isinstance(coll, bytes):
      return coll.decode('ascii')
    elif hasattr(coll, '__iter__') and not isinstance(coll, str):
      return [walk_json_dict(seq) for seq in coll]
    else:
      return coll
docs: Flatten a parsed SBP object into a dicts and lists, which are
    compatible for JSON output.
  
    Parameters
    ----------
    coll : dict