code: def mass_within_circle_in_units(self, radius: dim.Length, unit_mass='angular', kpc_per_arcsec=None,
                                      critical_surface_density=None):
          
  
          self.check_units_of_radius_and_critical_surface_density(
              radius=radius, critical_surface_density=critical_surface_density)
  
          profile = self.new_profile_with_units_converted(
              unit_length=radius.unit_length, unit_mass='angular',
              kpc_per_arcsec=kpc_per_arcsec, critical_surface_density=critical_surface_density)
  
          mass_angular = dim.Mass(value=quad(profile.mass_integral, a=0.0, b=radius, args=(1.0,))[0], unit_mass='angular')
          return mass_angular.convert(unit_mass=unit_mass, critical_surface_density=critical_surface_density)
docs: Integrate the mass profiles's convergence profile to compute the total mass within a circle of \
          specified radius. This is centred on the mass profile.
  
          The following units for mass can be specified and output:
  
          - Dimensionless angular units (default) - 'angular'.
          - Solar masses - 'angular' (multiplies the angular mass by the critical surface mass density).
  
          Parameters
          ----------
          radius : dim.Length
              The radius of the circle to compute the dimensionless mass within.
          unit_mass : str
              The units the mass is returned in (angular | angular).
          critical_surface_density : float or None
              The critical surface mass density of the strong lens configuration, which converts mass from angulalr \
              units to phsical units (e.g. solar masses).