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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 crval(self):
 """ Get the world coordinate of the reference pixel. @rtype: float, float """

        try:
            return self.wcs.crval1, self.wcs.crval2
        except Exception as ex:
            logging.debug("Couldn't get CRVAL from WCS: {}".format(ex))
            logging.debug("Trying RA/DEC values")

        try:
            return (float(self['RA-DEG']),
                    float(self['DEC-DEG']))
        except KeyError as ke:
            KeyError("Can't build CRVAL1/2 missing keyword: {}".format(ke.args[0]))