Update distributions.py

Author: NikitinaMaria

src/irt/distributions.py

@@ -37,6 +37,7 @@ class Beta(ExponentialFamily):
         concentration0 (float or Tensor): 2nd concentration parameter of the distribution
             (often referred to as beta)
     """
+
     arg_constraints = {
         "concentration1": constraints.positive,
         "concentration0": constraints.positive,