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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 requested_extent(self, extent):
 """Setter for extent property. :param extent: Analysis boundaries expressed as a QgsRectangle. The extent CRS should match the crs property of this IF instance. :type extent: QgsRectangle """

        if isinstance(extent, QgsRectangle):
            self._requested_extent = extent
            self._is_ready = False
        else:
            raise InvalidExtentError('%s is not a valid extent.' % extent)