Run black code formatter on kolmogorov_smirnov.py file

river/stats/kolmogorov_smirnov.py

@@ -285,4 +285,4 @@ def test_ks_threshold(self, ca):
         This test will return `True` if we **reject** the null hypothesis that
         the two windows follow the same distribution.
         """
-        return self.get() > ca * (2 * self.n_samples / self.n_samples ** 2) ** 0.5
+        return self.get() > ca * (2 * self.n_samples / self.n_samples**2) ** 0.5