code: def luminosity_within_ellipse_in_units(self, major_axis, unit_luminosity='eps', kpc_per_arcsec=None,
                                             exposure_time=None):
          
  
          if not isinstance(major_axis, dim.Length):
              major_axis = dim.Length(major_axis, 'arcsec')
  
          profile = self.new_profile_with_units_converted(unit_length=major_axis.unit_length,
                                                          unit_luminosity=unit_luminosity,
                                                          kpc_per_arcsec=kpc_per_arcsec, exposure_time=exposure_time)
          luminosity = quad(profile.luminosity_integral, a=0.0, b=major_axis, args=(self.axis_ratio,))[0]
          return dim.Luminosity(luminosity, unit_luminosity)
docs: Integrate the light profiles to compute the total luminosity within an ellipse of specified major axis. \
          This is centred on the light profile's centre.
  
          The following units for mass can be specified and output:
  
          - Electrons per second (default) - 'eps'.
          - Counts - 'counts' (multiplies the luminosity in electrons per second by the exposure time).
  
          Parameters
          ----------
          major_axis : float
              The major-axis radius of the ellipse.
          unit_luminosity : str
              The units the luminosity is returned in (eps | counts).
          exposure_time : float or None
              The exposure time of the observation, which converts luminosity from electrons per second units to counts.