code: def test_contraction():
      i, j, k, l = symbols("i,j,k,l", below_fermi=True)
      a, b, c, d = symbols("a,b,c,d", above_fermi=True)
      p, q, r, s = symbols("p,q,r,s")
      assert contraction(Fd(i), F(j)) == KroneckerDelta(i, j)
      assert contraction(F(a), Fd(b)) == KroneckerDelta(a, b)
      assert contraction(F(a), Fd(i)) == 0
      assert contraction(Fd(a), F(i)) == 0
      assert contraction(F(i), Fd(a)) == 0
      assert contraction(Fd(i), F(a)) == 0
      assert contraction(Fd(i), F(p)) == KroneckerDelta(i, p)
      restr = evaluate_deltas(contraction(Fd(p), F(q)))
      assert restr.is_only_below_fermi
      restr = evaluate_deltas(contraction(F(p), Fd(q)))
      assert restr.is_only_above_fermi
      raises(
          ContractionAppliesOnlyToFermions,
          lambda: contraction(B(a), Fd(b)),
      )
  
imports: from sympy.physics.secondquant import Dagger, Bd, VarBosonicBasis, BBra, B, BKet, FixedBosonicBasis, matrix_rep, apply_operators, InnerProduct, Commutator, KroneckerDelta, AnnihilateBoson, CreateBoson, BosonicOperator, F, Fd, FKet, BosonState, CreateFermion, AnnihilateFermion, evaluate_deltas, AntiSymmetricTensor, contraction, NO, wicks, PermutationOperator, simplify_index_permutations, _sort_anticommuting_fermions, _get_ordered_dummies, substitute_dummies, FockStateBosonKet, ContractionAppliesOnlyToFermions
  from sympy.concrete.summations import Sum
  from sympy.core.function import Function, expand
  from sympy.core.numbers import I, Rational
  from sympy.core.singleton import S
  from sympy.core.symbol import Dummy, Symbol, symbols
  from sympy.functions.elementary.miscellaneous import sqrt
  from sympy.printing.repr import srepr
  from sympy.simplify.simplify import simplify
  from sympy.testing.pytest import slow, raises
  from sympy.printing.latex import latex
label_desc: Use image node_id 24 for calling a global function with example usage: test_contraction() without return types