diff --git a/Lib/heapq.py b/Lib/heapq.py
index 00b429c..3bd064a 100644
--- a/Lib/heapq.py
+++ b/Lib/heapq.py
@@ -357,6 +357,10 @@ def merge(*iterables):
     [0, 1, 2, 3, 4, 5, 5, 7, 8, 10, 15, 20, 25]
 
     '''
+    if len(iterables) == 1:
+        yield from iterables[0]
+        return
+
     _heappop, _heapreplace, _StopIteration = heappop, heapreplace, StopIteration
 
     h = []