How do I set my font?

My code

import sys
from PySide2.QtCore import (QCoreApplication, QMetaObject, QObject, QPoint,
    QRect, QSize, QUrl, Qt)
from PySide2.QtGui import (QBrush, QColor, QConicalGradient, QCursor, QFont,
    QFontDatabase, QIcon, QLinearGradient, QPalette, QPainter, QPixmap,
    QRadialGradient)
from PySide2.QtWidgets import *


class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        if MainWindow.objectName():
            MainWindow.setObjectName(u"MainWindow")
        MainWindow.resize(1038, 722)
        self.centralwidget = QWidget(MainWindow)
        self.centralwidget.setObjectName(u"centralwidget")
        self.label = QLabel(self.centralwidget)
        self.label.setObjectName(u"label")
        self.label.setGeometry(QRect(10, 10, 191, 121))


        font_id = QFontDatabase.addApplicationFont(":/my_font.ttf")
        font = QFont("my_font", 12)
        font.setFamily(u"my_font")
        font.setBold(True)
        font.setWeight(75)
        self.label.setFont(font)

        self.label.setText('&#e435')



        MainWindow.setCentralWidget(self.centralwidget)
        self.menubar = QMenuBar(MainWindow)
        self.menubar.setObjectName(u"menubar")
        self.menubar.setGeometry(QRect(0, 0, 1038, 21))
        MainWindow.setMenuBar(self.menubar)
        self.statusbar = QStatusBar(MainWindow)
        self.statusbar.setObjectName(u"statusbar")
        MainWindow.setStatusBar(self.statusbar)

        self.retranslateUi(MainWindow)

        QMetaObject.connectSlotsByName(MainWindow)
    # setupUi

    def retranslateUi(self, MainWindow):
        MainWindow.setWindowTitle(QCoreApplication.translate("MainWindow", u"MainWindow", None))

StyleSheet = """
#centralwidget QWidget QWidget,
#centralwidget QWidget QWidget QWidget QWidget,
#centralwidget QWidget QWidget QWidget QWidget QWidget QWidget,
#centralwidget QWidget QWidget QWidget QWidget QWidget QWidget QWidget QWidget,
#centralwidget QWidget QWidget QWidget QWidget QWidget QWidget QWidget QWidget QWidget QWidget{
background:#000;
color:#fff;
}
#centralwidget QWidget,
#centralwidget QWidget QWidget QWidget,
#centralwidget QWidget QWidget QWidget QWidget QWidget,
#centralwidget QWidget QWidget QWidget QWidget QWidget QWidget QWidget,
#centralwidget QWidget QWidget QWidget QWidget QWidget QWidget QWidget QWidget QWidget{
background:#fff;
color:#000;
}
"""

class MainWindow(QMainWindow, Ui_MainWindow):
    def __init__(self, parent=None):
        super().__init__(parent)
        self.setupUi(self)

if __name__ == '__main__':
    app = QApplication(sys.argv)
    app.setStyleSheet(StyleSheet)
    window = MainWindow()
    window.show()
sys.exit(app.exec_())

I need the program to show me an icon instead of e435, but the problem is that I do not know how to connect the font. addApplicationFont () doesn't tell me if it found the font on this path or not. So I don't even know what the problem might be. Does anyone know the solution to this problem?