Issue #17047: remove doubled words found in 2.7 to 3.4 Lib/*,
as reported by Serhiy Storchaka and Matthew Barnett.
diff --git a/Lib/ftplib.py b/Lib/ftplib.py
index a0f0f90..8b733cf 100644
--- a/Lib/ftplib.py
+++ b/Lib/ftplib.py
@@ -464,7 +464,7 @@
           blocksize: The maximum data size to read from fp and send over
                      the connection at once.  [default: 8192]
           callback: An optional single parameter callable that is called on
-                    on each block of data after it is sent.  [default: None]
+                    each block of data after it is sent.  [default: None]
           rest: Passed to transfercmd().  [default: None]
 
         Returns:
@@ -486,7 +486,7 @@
           cmd: A STOR command.
           fp: A file-like object with a readline() method.
           callback: An optional single parameter callable that is called on
-                    on each line after it is sent.  [default: None]
+                    each line after it is sent.  [default: None]
 
         Returns:
           The response code.