code: def luminosity_within_circle_in_units(self, radius : dim.Length, unit_luminosity='eps', kpc_per_arcsec=None, exposure_time=None):
          
          if self.has_light_profile:
              return sum(map(lambda p: p.luminosity_within_circle_in_units(radius=radius, unit_luminosity=unit_luminosity,
                                                                           kpc_per_arcsec=kpc_per_arcsec, exposure_time=exposure_time),
                             self.light_profiles))
          else:
              return None
docs: Compute the total luminosity of the galaxy's light profiles within a circle of specified radius.
  
          See *light_profiles.luminosity_within_circle* for details of how this is performed.
  
          Parameters
          ----------
          radius : float
              The radius of the circle to compute the dimensionless mass within.
          unit_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.