bpo-36018: Make __pos__ return a distinct instance of NormDist (GH-12009)



https://bugs.python.org/issue36018
diff --git a/Lib/statistics.py b/Lib/statistics.py
index a73001a..bf10e19 100644
--- a/Lib/statistics.py
+++ b/Lib/statistics.py
@@ -762,7 +762,7 @@
         return NormalDist(x1.mu / x2, x1.sigma / fabs(x2))
 
     def __pos__(x1):
-        return x1
+        return NormalDist(x1.mu, x1.sigma)
 
     def __neg__(x1):
         return NormalDist(-x1.mu, x1.sigma)