def get_parameters(line):
    """Get parameters output by iostat.

    Args:
        line: Process line, hopefully containing the parameters.

    Returns:
        Tuple: (param_type, param_list)
        Where:
            param_type is one of ('avg-cpu:', 'Device:')
            param_list is a list of parameter names cleaned up for
                transmission, or empty list if the parameters could not
                be determined.
    """
    param_type = None
    param_list = []
    parts = line.split()
    if parts and parts[0] in ('avg-cpu:', 'Device:'):
        param_type = parts[0]
        for part in parts[1:]:
            for character in '/-%':
                if character in part:
                    part = part.replace(character, '_')
            param_list.append(part)
    return param_type, param_list