add tajimas d

Author: daletovar

sgkit/tests/test_popgen.py

@@ -53,6 +53,7 @@ def test_divergence(size):
     ts_div = ts.divergence([subset_1, subset_2], span_normalise=False)
     assert np.allclose(div, ts_div)
 
+
 @pytest.mark.parametrize("size", [2, 3, 10, 100])
 def test_Fst(size):
     ts = msprime.simulate(size, length=100, mutation_rate=0.05, random_seed=42)