def get_CC_operators():
 i = symbols('i', below_fermi=True, cls=Dummy)
 a = symbols('a', above_fermi=True, cls=Dummy)
 t_ai = AntiSymmetricTensor('t', (a,), (i,))
 ai = NO((Fd(a) * F(i)))
 (i, j) = symbols('i,j', below_fermi=True, cls=Dummy)
 (a, b) = symbols('a,b', above_fermi=True, cls=Dummy)
 t_abij = AntiSymmetricTensor('t', (a, b), (i, j))
 abji = NO((((Fd(a) * Fd(b)) * F(j)) * F(i)))
 T1 = (t_ai * ai)
 T2 = ((Rational(1, 4) * t_abij) * abji)
 return (T1, T2)

def get_CC_operators ( ) : i = symbols ( 'i' , below_fermi = True , cls = Dummy ) a = symbols ( 'a' , above_fermi = True , cls = Dummy ) t_ai = AntiSymmetricTensor ( 't' , ( a , ) , ( i , ) ) ai = NO ( ( Fd ( a ) * F ( i ) ) ) ( i , j ) = symbols ( 'i,j' , below_fermi = True , cls = Dummy ) ( a , b ) = symbols ( 'a,b' , above_fermi = True , cls = Dummy ) t_abij = AntiSymmetricTensor ( 't' , ( a , b ) , ( i , j ) ) abji = NO ( ( ( ( Fd ( a ) * Fd ( b ) ) * F ( j ) ) * F ( i ) ) ) T1 = ( t_ai * ai ) T2 = ( ( Rational ( 1 , 4 ) * t_abij ) * abji ) return ( T1 , T2 )
returns a tuple of unique operators .