def isCountRate(self):
        """
        isCountRate: Method or IRInputObject used to indicate if the
        science data is in units of counts or count rate.  This method
        assumes that the keyword 'BUNIT' is in the header of the input
        FITS file.
        """
        has_bunit = False
        if 'BUNIT' in self._image['sci',1].header :
            has_bunit = True

        countrate = False
        if (self._image[0].header['UNITCORR'].strip() == 'PERFORM') or \
            (has_bunit and self._image['sci',1].header['bunit'].find('/') != -1) :
            countrate = True

        return countrate
isCountRate: Method or IRInputObject used to indicate if the
        science data is in units of counts or count rate.  This method
        assumes that the keyword 'BUNIT' is in the header of the input
        FITS file.