bpo-42470: Do not warn on sequences which are also sets in random.sample() (GH-23665)

1 files changed, 7 insertions, 6 deletions

diff --git a/Lib/random.py b/Lib/random.py
index 139e8a4..66433ba 100644
--- a/Lib/random.py
+++ b/Lib/random.py
@@ -424,13 +424,14 @@ class Random(_random.Random):
         # too many calls to _randbelow(), making them slower and
         # causing them to eat more entropy than necessary.
 
-        if isinstance(population, _Set):
-            _warn('Sampling from a set deprecated\n'
-                  'since Python 3.9 and will be removed in a subsequent version.',
-                  DeprecationWarning, 2)
-            population = tuple(population)
         if not isinstance(population, _Sequence):
-            raise TypeError("Population must be a sequence.  For dicts or sets, use sorted(d).")
+            if isinstance(population, _Set):
+                _warn('Sampling from a set deprecated\n'
+                      'since Python 3.9 and will be removed in a subsequent version.',
+                      DeprecationWarning, 2)
+                population = tuple(population)
+            else:
+                raise TypeError("Population must be a sequence.  For dicts or sets, use sorted(d).")
         n = len(population)
         if counts is not None:
             cum_counts = list(_accumulate(counts))