<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_observation_coordinates(self, x, y, hdulist_index):
 """ Retrieves the location of a point using the coordinate system of the original observation, i.e. the original image before any cutouts were done. Returns: (x, y) in the original image coordinate system. @param x: x-pixel location in the cutout frame of reference @param y: y-pixel location in the cutout frame of reference @param idx: index of hdu in hdulist that the given x/y corresponds to. """

        return self.hdulist[hdulist_index].converter.get_inverse_converter().convert((x, y))