Getting mouse Locations in Coordenates

Hi you all,

I am trying to get the mouse location in coordenates, i have been able to get the X and Y position in pixels however getting the location in coordinates has not been possible. My code as follows:

···

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self.figura = Figure(figsize=(8,4), facecolor=0.99, dpi=70, frameon=True)
self.vista=self.figura.add_subplot(111)
self.canvas = FigureCanvasGTK(self.figura)
self.canvas.connect("button_press_event", self.location)
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def location(self,widget, event):
   print event.x, event.y
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however when i try:
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def location(self,widget, event):
   print event.x, event.y
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i do get the folowing:

AttributeError: xdata

Any sugestion to get the xdata value??

Thanks for your answers, any help highly appretiated

Juan