错误提示NameError: name ‘Ui_Form‘ is not defined _nameerror: name 'ui' is not defined

参照https://www.cnblogs.com/lizm166/p/10286555.html这篇文章里的教程，实践了一下pycharm+qt5开发，代码如下：

# -*- coding: utf-8 -*-
 
# Form implementation generated from reading ui file 'jisuan.ui'
#
# Created by: PyQt5 UI code generator 5.12.3
#
# WARNING! All changes made in this file will be lost!
 
 
from PyQt5 import QtCore, QtGui, QtWidgets
print(__name__)
 
class Ui_Form(object):
    def setupUi(self, Form):
        Form.setObjectName("Form")
        Form.resize(1121, 851)
        self.pushButton = QtWidgets.QPushButton(Form)
        self.pushButton.setGeometry(QtCore.QRect(740, 70, 93, 28))
        font = QtGui.QFont()
        font.setPointSize(12)
        font.setBold(True)
        font.setWeight(75)
        self.pushButton.setFont(font)
        self.pushButton.setAutoDefault(True)
        self.pushButton.setDefault(True)
        self.pushButton.setFlat(False)
        self.pushButton.setObjectName("pushButton")
        self.lineEdit = QtWidgets.QLineEdit(Form)
        self.lineEdit.setGeometry(QtCore.QRect(80, 70, 113, 21))
        self.lineEdit.setObjectName("lineEdit")
        self.lineEdit_2 = QtWidgets.QLineEdit(Form)
        self.lineEdit_2.setGeometry(QtCore.QRect(300, 70, 113, 21))
        self.lineEdit_2.setObjectName("lineEdit_2")
        self.label = QtWidgets.QLabel(Form)
        self.label.setGeometry(QtCore.QRect(210, 70, 61, 20))
        font = QtGui.QFont()
        font.setPointSize(14)
        font.setBold(True)
        font.setWeight(75)
        self.label.setFont(font)
        self.label.setAlignment(QtCore.Qt.AlignCenter)
        self.label.setObjectName("label")
        self.label_2 = QtWidgets.QLabel(Form)
        self.label_2.setGeometry(QtCore.QRect(450, 70, 72, 15))
        font = QtGui.QFont()
        font.setPointSize(15)
        font.setBold(True)
        font.setWeight(75)
        self.label_2.setFont(font)
        self.label_2.setAlignment(QtCore.Qt.AlignCenter)
        self.label_2.setObjectName("label_2")
        self.lineEdit_3 = QtWidgets.QLineEdit(Form)
        self.lineEdit_3.setGeometry(QtCore.QRect(560, 70, 113, 21))
        self.lineEdit_3.setObjectName("lineEdit_3")
 
        self.retranslateUi(Form)
        QtCore.QMetaObject.connectSlotsByName(Form)
 
    def retranslateUi(self, Form):
        _translate = QtCore.QCoreApplication.translate
        Form.setWindowTitle(_translate("Form", "Form"))
        self.pushButton.setText(_translate("Form", "计算"))
        self.label.setText(_translate("Form", "   +"))
        self.label_2.setText(_translate("Form", "="))
 
    if __name__ == "__main__":
        import sys
        from PyQt5.QtGui import QIcon
        app = QtWidgets.QApplication(sys.argv)
        widget = QtWidgets.QWidget()
        ui = Ui_Form()
        ui.setupUi(widget)
        widget.setWindowIcon(QIcon('web.png'))  # 增加icon图标，如果没有图片可以没有这句
        widget.show()
        sys.exit(app.exec_())
 

但运行提示错误：NameError: name 'Ui_Form' is not defined 

原因：代码格式没对齐，要把

if __name__ == "__main__":的代码顶格写，如下所示

if __name__ == "__main__":
    import sys
    from PyQt5.QtGui import QIcon
    app = QtWidgets.QApplication(sys.argv)
    widget = QtWidgets.QWidget()
    ui = Ui_Form()
    ui.setupUi(widget)
    widget.setWindowIcon(QIcon('web.png'))  # 增加icon图标，如果没有图片可以没有这句
    widget.show()
    sys.exit(app.exec_())