diff --git a/Lib/pstats.py b/Lib/pstats.py
index 6beb0b3..0effa1c 100644
--- a/Lib/pstats.py
+++ b/Lib/pstats.py
@@ -649,7 +649,7 @@
 
         def do_sort(self, line):
             abbrevs = self.stats.get_sort_arg_defs()
-            if line and not filter(lambda x,a=abbrevs: x not in a,line.split()):
+            if line and all((x in abbrevs) for x in line.split()):
                 self.stats.sort_stats(*line.split())
             else:
                 print >> self.stream, "Valid sort keys (unique prefixes are accepted):"