def load_policy_line(line, model):
    """loads a text line as a policy rule to model."""
    if line == '':
        return
    if line[:1] == '#':
        return
    tokens = line.split(', ')
    key = tokens[0]
    sec = key[0]
    if sec not in model.model.keys():
        return
    if key not in model.model[sec].keys():
        return
    model.model[sec][key].policy.append(tokens[1:])
