How to use the pyuvdata.utils.polnum2str function in pyuvdata

def get_pols(self):
        """
        Returns list of pols in string format.
        """
        return uvutils.polnum2str(self.polarization_array)

if len(polarizations) == 0:
            polarizations = None
        else:
            polarizations.sort(reverse=True)

        if print_toggle:
            print('\nParsed antenna pairs:')
            if ant_pairs_nums is not None:
                for pair in ant_pairs_nums:
                    print(pair)

            print('\nParsed polarizations:')
            if polarizations is not None:
                for pol in polarizations:
                    print(uvutils.polnum2str(pol))

        if len(warned_ants) > 0:
            warnings.warn('Warning: Antenna number {a} passed, but not present '
                          'in the ant_1_array or ant_2_array'
                          .format(a=(',').join(map(str, warned_ants))))

        if len(warned_pols) > 0:
            warnings.warn('Warning: Polarization {p} is not present in '
                          'the polarization_array'
                          .format(p=(',').join(warned_pols).upper()))

        return ant_pairs_nums, polarizations

def get_pols(self):
        """
        Get the polarizations in the data.

        Returns
        -------
        list of str
            list of polarizations (as strings) in the data.
        """
        return uvutils.polnum2str(
            self.polarization_array, x_orientation=self.x_orientation
        )