def _show_consistency(field, message, is_consistent):
    """
    If `is_consistent` is false,
    make `field` RED with tooltip caption `message`.
    Otherwise reset colour and tooltip caption of `field` to default values.
    """
    if is_consistent is True:
        field.setStyleSheet('')
        field.setToolTip('')
    else:
        field.setStyleSheet('QLineEdit { background-color : red;}')
        field.setToolTip(message)
