Remove duplication.
diff --git a/Lib/rfc822.py b/Lib/rfc822.py
index 64cd702..3b29a6a 100644
--- a/Lib/rfc822.py
+++ b/Lib/rfc822.py
@@ -34,7 +34,7 @@
libraries in which tell() discards buffered data before discovering that the
lseek() system call doesn't work. For maximum portability, you should set the
seekable argument to zero to prevent that initial \code{tell} when passing in
-an unseekable object such as a a file object created from a socket object. If
+an unseekable object such as a file object created from a socket object. If
it is 1 on entry -- which it is by default -- the tell() method of the open
file object is called once; if this raises an exception, seekable is reset to
0. For other nonzero values of seekable, this test is not made.