I have given my code below, have problem in implementing a function

I want the text in lineedit with objectname 'host' in a string say 'shost'. when the user click the pushbutton with name 'connect'.How do i do it? I tried and failed. How to implement this function?

import sys
from PyQt4.QtCore import *
from PyQt4.QtGui import *


class Form(QDialog):
    def __init__(self, parent=None):
        super(Form, self).__init__(parent)

        le = QLineEdit()
        le.setObjectName("host")
 le.setText("Host")
 pb = QPushButton()
 pb.setObjectName("connect")
 pb.setText("Connect") 
 layout.addWidget(le)
 layout.addWidget(pb)
        self.setLayout(layout)

 self.connect(pb, SIGNAL("clicked()"),self.button_click)

        self.setWindowTitle("Learning")

    def button_click(self):
    #i want the text in lineedit with objectname 
 #'host' in a string say 'shost'. when the user click 
 # the pushbutton with name connect.How do i do it?
 # I tried and failed. How to implement this function?




app = QApplication(sys.argv)
form = Form()
form.show()
app.exec_()

Now how do i implement the function "def button_click(self):" ? I have just started with pyQt!