code: def _vmomentsurfaceIntegrand(vz,vR,vT,R,z,df,sigmaR1,gamma,sigmaz1,n,m,o): #pragma: no cover because this is too slow; a warning is shown
      
      return vR**n*vT**m*vz**o*df(R,vR*sigmaR1,vT*sigmaR1*gamma,z,vz*sigmaz1,
                                  use_physical=False)
docs: Internal function that is the integrand for the vmomentsurface mass integration