[newbie] Python and Qt4 Designer

[Jean Dubois]

I'm trying to combine python-code made with QT4 designer with plain
python statements like
file = open("test","w")
Can anyone tell me what I have to  add to the following code just to
open a file when clicking on the load-button and closing it by
clicking on the save button.

#!/usr/bin/env python
# -*- coding: utf-8 -*-

# Form implementation generated from reading ui file 'test.ui'
#
# Created: Wed Jul 11 17:21:35 2012
#      by: PyQt4 UI code generator 4.8.3
#
# WARNING! All changes made in this file will be lost!

from PyQt4 import QtCore, QtGui

try:
    _fromUtf8 = QtCore.QString.fromUtf8
except AttributeError:
    _fromUtf8 = lambda s: s

class Ui_Form(object):
    def setupUi(self, Form):
        Form.setObjectName(_fromUtf8("Form"))
        Form.resize(400, 300)
        self.widget = QtGui.QWidget(Form)
        self.widget.setGeometry(QtCore.QRect(10, 20, 146, 25))
        self.widget.setObjectName(_fromUtf8("widget"))
        self.horizontalLayout = QtGui.QHBoxLayout(self.widget)
        self.horizontalLayout.setMargin(0)
 
self.horizontalLayout.setObjectName(_fromUtf8("horizontalLayout"))
        self.pushButton_2 = QtGui.QPushButton(self.widget)
        self.pushButton_2.setObjectName(_fromUtf8("pushButton_2"))
        self.horizontalLayout.addWidget(self.pushButton_2)
        self.pushButton = QtGui.QPushButton(self.widget)
        self.pushButton.setObjectName(_fromUtf8("pushButton"))
        self.horizontalLayout.addWidget(self.pushButton)

        self.retranslateUi(Form)
        QtCore.QMetaObject.connectSlotsByName(Form)

    def retranslateUi(self, Form):
        Form.setWindowTitle(QtGui.QApplication.translate("Form",
"Form", None, QtGui.QApplication.UnicodeUTF8))
        self.pushButton_2.setText(QtGui.QApplication.translate("Form",
"Save file", None, QtGui.QApplication.UnicodeUTF8))
        self.pushButton.setText(QtGui.QApplication.translate("Form",
"Load file", None, QtGui.QApplication.UnicodeUTF8))


if __name__ == "__main__":
    import sys
    app = QtGui.QApplication(sys.argv)
    Form = QtGui.QWidget()
    ui = Ui_Form()
    ui.setupUi(Form)
    Form.show()
    sys.exit(app.exec_())


thanks in advance
jean