import PyQt4
from PyQt4 import QtGui,QtCore, uic

ui_file = 'my_qt_design_ui_file.ui' # in Qt Designer, the pushButton object name is set as "my_pushButton"
form, base = uic.loadUiType(ui_file)

class TestWinUI(base, form):
    def __init__(self):
        super(base,self).__init__()
        self.setupUi(self)
        self.Establish_Connections()
    
    # handler functions
    def my_btn_fn(self):  
        print('do something')    

    # action listener binding
    def Establish_Connections(self):
        # old connection
        QtCore.QObject.connect(self.my_pushButton, QtCore.SIGNAL("clicked()"),self.my_btn_fn)
        # new connection format
        #self.my_pushButton.clicked.connect(self.my_btn_fn)

def main():
    global myWin
    myWin=TestWinUI()
    myWin.show()
    
if __name__=="__main__":
    main()