def E_nl(n, l, hw):
 return ((((2 * n) + l) + Rational(3, 2)) * hw)

def E_nl ( n , l , hw ) : return ( ( ( ( 2 * n ) + l ) + Rational ( 3 , 2 ) ) * hw )
returns the energy of an isotropic harmonic oscillator n the "nodal" quantum number l the orbital angular momentum hw the harmonic oscillator parameter .