code: def transform(self, maps):
          
          out = {}
          out[parameters.distance] = \
                  conversions.distance_from_chirp_distance_mchirp(
                                                      maps[parameters.chirp_distance],
                                                      maps[parameters.mchirp],
                                                      ref_mass=self.ref_mass)
          return self.format_output(maps, out)
docs: This function transforms from chirp distance to luminosity distance,
          given the chirp mass.
  
          Parameters
          ----------
          maps : a mapping object
  
          Examples
          --------
          Convert a dict of numpy.array:
  
          >>> import numpy as np
          >>> from pycbc import transforms
          >>> t = transforms.ChirpDistanceToDistance()
          >>> t.transform({'chirp_distance': np.array([40.]), 'mchirp': np.array([1.2])})
          {'mchirp': array([ 1.2]), 'chirp_distance': array([ 40.]), 'distance': array([ 39.48595679])}
  
          Returns
          -------
          out : dict
              A dict with key as parameter name and value as numpy.array or float
              of transformed values.