как установить несколько пользовательских проставок в PyQt5

Question

Я хочу установить пользовательские разделители для отдельного разделения виджетов. Я установил 3 проставки, которые должны по-разному расширяться в вертикальном направлении, но расстояние между виджетами остается одинаковым.

verticalSpacer1 = qtw.QSpacerItem(1, 40, qtw.QSizePolicy.Minimum, 
                                  vPolicy=qtw.QSizePolicy.Expanding)

и

verticalSpacer2 = qtw.QSpacerItem(10, 3, qtw.QSizePolicy.Minimum, 
                                  vPolicy=qtw.QSizePolicy.Expanding)

Похоже, VBoxLayout занимает только параметры одной проставки.

#!/usr/bin/env python

"""

file

"""

import os
import sys
from PyQt5 import QtWidgets as qtw
from PyQt5 import QtCore as qtc
from PyQt5 import QtGui as qtg




class ChooseTest(qtw.QWidget):
    """
    remit to one of three tests if widgets toggled/clicked
    hide its self after
    """

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        # your code will go here

        # interface not move
        self.setWindowFlags(qtc.Qt.FramelessWindowHint| qtc.Qt.SubWindow)



        self.setWindowModality(qtc.Qt.ApplicationModal)


        # position
        qtRectangle = self.frameGeometry()
        centerPoint = qtw.QDesktopWidget().availableGeometry().center()
        qtRectangle.moveCenter(centerPoint)
        # self.move(qtRectangle.topLeft())
        # size
        self.resize(400, 310)

        # heading
        heading_label = qtw.QLabel("Heading")
        heading_label.setAlignment(qtc.Qt.AlignHCenter)

        # widgets
        comobox_selectpressen = qtw.QComboBox()
        comobox_selectpressen.setFixedWidth(130)

        comobox_selectquality = qtw.QComboBox()
        comobox_selectquality.setFixedWidth(130)

        start_test_label = qtw.QLabel("beginn")

        self.start_button = qtw.QPushButton("beginn 1")
        self.start_button.setFixedWidth(130)

        self.back_button = qtw.QPushButton("back to")
        self.back_button.setFixedWidth(130)


        # nested layout
        hblayout_combo = qtw.QHBoxLayout()


        hblayout_combo.addStretch(2)

        hblayout_combo.addWidget(comobox_selectpressen)
        hblayout_combo.addStretch(1)
        hblayout_combo.addWidget(comobox_selectquality)
        hblayout_combo.addStretch(2)

        # start_button layout
        hlayout_startbutton = qtw.QHBoxLayout()
        hlayout_startbutton.addStretch(1)
        hlayout_startbutton.addWidget(self.start_button)
        hlayout_startbutton.addStretch(1)

        # back_button layout
        hlayout_backbutton = qtw.QHBoxLayout()
        hlayout_backbutton.addStretch(1)
        hlayout_backbutton.addWidget(self.back_button)
        hlayout_backbutton.addStretch(1)




        # spacer
        verticalSpacer1 = qtw.QSpacerItem(1, 40, qtw.QSizePolicy.Minimum, vPolicy=qtw.QSizePolicy.Expanding)

        verticalSpacer2 = qtw.QSpacerItem(10, 3, qtw.QSizePolicy.Minimum, vPolicy=qtw.QSizePolicy.Expanding)


        verticalSpacer3 = qtw.QSpacerItem(3, 4, vPolicy=qtw.QSizePolicy.Expanding)
        # @spacer = new QSpacerItem(40, 20, QSizePolicy::Minimum, QSizePolicy::Expanding);@

        # mainlayout
        main_layout = qtw.QVBoxLayout()


        main_layout.addWidget(heading_label)
        main_layout.addSpacerItem(verticalSpacer2)


        main_layout.addLayout(hblayout_combo)

        main_layout.addSpacerItem(verticalSpacer1)

        main_layout.addLayout(hlayout_startbutton)
        main_layout.addItem(verticalSpacer3)

        main_layout.addLayout(hlayout_backbutton)


        self.setLayout(main_layout)

        # functionality


        self.show()



if __name__ == '__main__':
    app = qtw.QApplication(sys.argv)
    w = ChooseTest()
    sys.exit(app.exec_())