Remove redundant assignment l = [] from poll3() -- copy-and-paste
error.
diff --git a/Lib/asyncore.py b/Lib/asyncore.py
index ec769db..8761365 100644
--- a/Lib/asyncore.py
+++ b/Lib/asyncore.py
@@ -146,7 +146,6 @@
     timeout = int(timeout*1000)
     pollster = select.poll()
     if map:
-        l = []
         for fd, obj in map.items():
             flags = 0
             if obj.readable():