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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def totalNumberOfTiles(self, minZoom=None, maxZoom=None):
        "Return the total number of tiles for this instance extent"
        nbTiles = 0
        minZoom = minZoom or 0
        if maxZoom:
            maxZoom = maxZoom + 1
        else:
            maxZoom = len(self.RESOLUTIONS)
        for zoom in xrange(minZoom, maxZoom):
            nbTiles += self.numberOfTilesAtZoom(zoom)
        return nbTiles