PyQt: show SVG

#scale increase 
self.connect(self.incScaleButton, QtCore.SIGNAL("clicked()"),lambda who="incScale": self.incScale())
 #scale decrease 
 self.connect(self.decScaleButton, QtCore.SIGNAL("clicked()"),lambda who="decScale": self.decScale())
 #create Scene for show diagrams
 self.sc=QtGui.QGraphicsScene(self.graphicsView)

 def incScale(self):
     self.scale+=0.1
     self.printGDP(scale=self.scale)

 def decScale(self):
     self.scale-=0.1
     self.printGDP(scale=self.scale)

 #show diagram: 
 filename=fileArrayt[fileNumber]
 #create object for SVG modification 
 r=QtSvg.QSvgRenderer()
 #load data 
 r.load(QtCore.QByteArray(arrayToSave))
 #change rectangle for our image 
 r.setViewBox(QtCore.QRectF(0.0, 0.0, 3200.0, 2000))
 #create additional element
 item=QtSvg.QGraphicsSvgItem()
 #put our image into it 
 item.setSharedRenderer(r)
 #change scale
 item.setScale(1.0)
 #clear Scene, change size of it 
 self.sc.clear()
 self.sc.setSceneRect(QtCore.QRectF(0.0, 0.0, 3200.0, 2000))
 #change position of item into Scene 
 item.setPos(QtCore.QPointF(10,50))
 #add item to Scene 
 self.sc.addItem(item)
 #for QGraphicsView set Scene, define "view point" 
 self.graphicsView.setScene(self.sc)
 self.graphicsView.centerOn(0,0)