def transform(self, maps):
        """ This function transforms from distance to redshift.

        Parameters
        ----------
        maps : a mapping object

        Examples
        --------
        Convert a dict of numpy.array:

        >>> import numpy
        >>> from pycbc import transforms
        >>> t = transforms.DistanceToRedshift()
        >>> t.transform({'distance': numpy.array([1000])})
            {'distance': array([1000]), 'redshift': 0.19650987609144363}

        Returns
        -------
        out : dict
            A dict with key as parameter name and value as numpy.array or float
            of transformed values.
        """
        out = {parameters.redshift : cosmology.redshift(
                                                    maps[parameters.distance])}
        return self.format_output(maps, out)
This function transforms from distance to redshift.

        Parameters
        ----------
        maps : a mapping object

        Examples
        --------
        Convert a dict of numpy.array:

        >>> import numpy
        >>> from pycbc import transforms
        >>> t = transforms.DistanceToRedshift()
        >>> t.transform({'distance': numpy.array([1000])})
            {'distance': array([1000]), 'redshift': 0.19650987609144363}

        Returns
        -------
        out : dict
            A dict with key as parameter name and value as numpy.array or float
            of transformed values.