interfaces/python/demo_sink.py: fix number of arguments

diff --git a/interfaces/python/demo_sink.py b/interfaces/python/demo_sink.py
index 230a28de6a91735b1bb5adddc0b93301d7ffe937..6226650e9aeed9eef1ef73b112c7d01dd9a54aef 100755 (executable)
--- a/interfaces/python/demo_sink.py
+++ b/interfaces/python/demo_sink.py
@@ -4,7 +4,7 @@ import sys
 from aubio import source, sink
 
 if __name__ == '__main__':
-  if len(sys.argv) < 2:
+  if len(sys.argv) < 3:
     print 'usage: %s <inputfile> <outputfile>' % sys.argv[0]
     sys.exit(1)
   f = source(sys.argv[1], 8000, 256)