mouse move event filtering in PyQt4

Hi,
I need to filter mouse moving on a QGraphicsView in PyQt4. I created a filter and install it to a QGraphicsView instance, but desired event seems not to be captured.

Following a simple example showing how no mouse moving is filtered by eventFilter() function:

Code:

import sys
 
from PyQt4 import QtCore, QtGui
 
class Filter(QtCore.QObject):
	def eventFilter(self, obj, event):
    	print event.type()
    	return False
 
class MainWin(QtGui.QMainWindow):
 
	def __init__(self, parent=None, flags=QtCore.Qt.Widget):
    	QtGui.QMainWindow.__init__(self, parent, flags)
 
    	self.scene = QtGui.QGraphicsScene(self)
    	self.graphicsview = QtGui.QGraphicsView(self.scene, self)
    	self.graphicsview.setMouseTracking(True)
    	self.filter = Filter(self.graphicsview)
    	self.graphicsview.installEventFilter(self.filter)
    	self.setCentralWidget(self.graphicsview)
 
def main():
	app = QtGui.QApplication(sys.argv)
	mainwin = MainWin()
	mainwin.show()
	sys.exit(app.exec_())
 
if __name__ == '__main__':
	main()

Thanks to all ones that answer after reading this very complex code