code: def luminosities_of_galaxies_within_circles_in_units(self, radius : dim.Length, unit_luminosity='eps', exposure_time=None):
          
          return list(map(lambda galaxy: galaxy.luminosity_within_circle_in_units(
              radius=radius, unit_luminosity=unit_luminosity, kpc_per_arcsec=self.kpc_per_arcsec,
              exposure_time=exposure_time),
                          self.galaxies))
docs: Compute the total luminosity of all galaxies in this plane within a circle of specified radius.
  
          See *galaxy.light_within_circle* and *light_profiles.light_within_circle* for details \
          of how this is performed.
  
          Parameters
          ----------
          radius : float
              The radius of the circle to compute the dimensionless mass within.
          units_luminosity : str
              The units the luminosity is returned in (eps | counts).
          exposure_time : float
              The exposure time of the observation, which converts luminosity from electrons per second units to counts.