code: def askRasterBounds(self):
          
          dlg = RasterBoundsDialog(bounds= (self.rasterBottom, self.rasterTop))
          if dlg.exec_():
              bounds = dlg.values()
              self.setRasterBounds(bounds)
docs: Prompts the user to provide the raster bounds with a dialog. 
          Saves the bounds to be applied to the plot