def METHOD_NAME(op):
    """
    Replaces Digest/BasicDigest for Basic
    :param obj op: file operations object
    """
    try:
        lines = op.readlines(CUPSD_CONF)
    except IOError as error:
        raise IOError(error)
    for line in lines:
        for directive in ['AuthType', 'DefaultAuthType']:
            if line.lstrip().startswith(directive):
                auth_line_value = line.lstrip().lstrip(directive).lstrip()
                for value in ['Digest', 'BasicDigest']:
                    if auth_line_value.startswith(value):
                        lines[lines.index(line)] = '{} Basic\n'.format(directive)
    op.write(CUPSD_CONF, 'w', lines)