diff --git a/Lib/random.py b/Lib/random.py
index 7210f62..2530c39 100644
--- a/Lib/random.py
+++ b/Lib/random.py
@@ -258,6 +258,10 @@
                 result[i] = pool[j]
                 pool[j] = pool[n-i-1]   # move non-selected item into vacancy
         else:
+            try:
+                n > 0 and (population[0], population[n//2], population[n-1])
+            except (TypeError, KeyError):   # handle sets and dictionaries
+                population = tuple(population)
             selected = {}
             for i in xrange(k):
                 j = _int(random() * n)