def rule_1(doc):
    """ Validate :ref:`ags4_rule_1`

    :param raw_str:
    :rtype: tuple
    :return:
        - A list of ags_errors
        - A list of sys_errors
    """
    warnings = []
    errors = []
    try:
        doc.source.decode('ascii')
        return warnings, errors
    except UnicodeDecodeError:
        errors.append('Unicode decode error')
        for lidx, line in enumerate(doc.source.split('\n')):
            for cidx, charlie in enumerate(line):
                if ord(charlie) < 128:
                    pass
                else:
                    warnings.append(dict(line=lidx + 1, column=cidx + 1,
                        illegal=[]))
    return warnings, errors
