Convert all print statements in the docs.
diff --git a/Doc/library/signal.rst b/Doc/library/signal.rst
index 94f305c..d3c498d 100644
--- a/Doc/library/signal.rst
+++ b/Doc/library/signal.rst
@@ -143,7 +143,7 @@
    import signal, os
 
    def handler(signum, frame):
-       print 'Signal handler called with signal', signum
+       print('Signal handler called with signal', signum)
        raise IOError("Couldn't open device!")
 
    # Set the signal handler and a 5-second alarm