Implements indentation pre event input accelerators.

    :param editor: Document editor.
    :type editor: QWidget
    :param event: Event being handled.
    :type event: QEvent
    :return: Process event.
    :rtype: bool

def indentation_pre_event_input_accelerators(editor, event):
    """
    Implements indentation pre event input accelerators.

    :param editor: Document editor.
    :type editor: QWidget
    :param event: Event being handled.
    :type event: QEvent
    :return: Process event.
    :rtype: bool
    """

    process_event = True
    if not hasattr(editor, "indent"):
        return process_event

    if event.key() == Qt.Key_Tab:
        process_event = editor.indent() and False
    elif event.key() == Qt.Key_Backtab:
        process_event = editor.unindent() and False
    return process_event