code: def mass_within_circle_in_units(self, radius, unit_mass='angular', kpc_per_arcsec=None, critical_surface_density=None):
          
          if self.has_mass_profile:
              return sum(map(lambda p: p.mass_within_circle_in_units(radius=radius, unit_mass=unit_mass,
                                                                     kpc_per_arcsec=kpc_per_arcsec,
                                                                     critical_surface_density=critical_surface_density),
                             self.mass_profiles))
          else:
              return None
docs: Compute the total angular mass of the galaxy's mass profiles within a circle of specified radius.
  
          See *profiles.mass_profiles.mass_within_circle* for details of how this is performed.
  
          Parameters
          ----------
          radius : float
              The radius of the circle to compute the dimensionless mass within.
          unit_mass : str
              The units the mass is returned in (angular | solMass).
          critical_surface_density : float
              The critical surface mass density of the strong lens configuration, which converts mass from angulalr \
              units to physical units (e.g. solar masses).