<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def parse_radl(data):
 """ Parse a RADL document in JSON. Args.: - data(str or list):
 document to parse. Return(RADL):
 RADL object. """

    if not isinstance(data, list):
        if os.path.isfile(data):
            f = open(data)
            data = "".join(f.readlines())
            f.close()
        data = json.loads(data)
    data = encode_simple(data)
    res = RADL()
    for aspect in [p_aspect(a) for a in data]:
        res.add(aspect)
    return res