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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 _make_mask(self, data, lon_str=LON_STR, lat_str=LAT_STR):
 """Construct the mask that defines a region on a given data's grid."""

        mask = False
        for west, east, south, north in self.mask_bounds:
            if west < east:
                mask_lon = (data[lon_str] > west) & (data[lon_str] < east)
            else:
                mask_lon = (data[lon_str] < west) | (data[lon_str] > east)
            mask_lat = (data[lat_str] > south) & (data[lat_str] < north)
            mask |= mask_lon & mask_lat
        return mask