From e11a47e2070c9c271da5b26a77c8ab50437e58b4 Mon Sep 17 00:00:00 2001
From: Raymond Hettinger <python@rcn.com>
Date: Sun, 30 Oct 2011 14:29:06 -0700
Subject: [PATCH] Issue 13274:  Make the pure python code for heapq more
 closely match the C implementation for an undefined corner case.

---
 Lib/heapq.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Lib/heapq.py b/Lib/heapq.py
index fcaca134422..6a4e0f4c31c 100644
--- a/Lib/heapq.py
+++ b/Lib/heapq.py
@@ -193,6 +193,8 @@ def nlargest(n, iterable):
 
     Equivalent to:  sorted(iterable, reverse=True)[:n]
     """
+    if n < 0:
+        return []
     it = iter(iterable)
     result = list(islice(it, n))
     if not result:
@@ -209,6 +211,8 @@ def nsmallest(n, iterable):
 
     Equivalent to:  sorted(iterable)[:n]
     """
+    if n < 0:
+        return []
     if hasattr(iterable, '__len__') and n * 10 <= len(iterable):
         # For smaller values of n, the bisect method is faster than a minheap.
         # It is also memory efficient, consuming only n elements of space.