我用PyQt创建了一个UI文件，然后新建了一个py文件，我想在这个新文件内引用一个LineEdit，UI文件的部分代码如下
class Ui_MainWindow(object):
def setupUi(self, MainWindow):
MainWindow.setObjectName(_fromUtf8("MainWindow"))
MainWindow.resize(1124, 623)
self.centralwidget = QtGui.QWidget(MainWindow)
self.centralwidget.setObjectName(_fromUtf8("centralwidget"))
self.label_3 = QtGui.QLabel(self.centralwidget)
self.label_3.setGeometry(QtCore.QRect(190, 110, 131, 31))
font = QtGui.QFont()
font.setPointSize(14)
self.label_3.setFont(font)
self.label_3.setMidLineWidth(0)
self.label_3.setObjectName(_fromUtf8("label_3"))
self.LineEdit = QtGui.QLineEdit(self.centralwidget)
self.LineEdit.setGeometry(QtCore.QRect(330, 110, 501, 31))
self.LineEdit.setObjectName(_fromUtf8("LineEdit_2"))
我想引用那个LineEdit，然后自己文件里写的代码
import sys
reload(sys)
sys.setdefaultencoding('utf8')
from UI import Ui_MainWindow
def hist():
stock_code = Ui_MainWindow.LineEdit.text()
print (stock_code)
然后就会报错AttributeError: type object 'Ui_MainWindow' has no attribute 'LineEdit'
该怎么解决啊，新手先谢过各位大大了
