Use string.ascii_letters instead of string.letters (SF bug #226706).
Work-around a font-lock bogosity.
diff --git a/Lib/pipes.py b/Lib/pipes.py
index aaad0eb..1e16435 100644
--- a/Lib/pipes.py
+++ b/Lib/pipes.py
@@ -3,8 +3,8 @@
The problem:
------------
-Suppose you have some data that you want to convert to another format
-(e.g. from GIF image format to PPM image format). Maybe the
+Suppose you have some data that you want to convert to another format,
+such as from GIF image format to PPM image format. Maybe the
conversion involves several steps (e.g. piping it through compress or
uuencode). Some of the conversion steps may require that their input
is a disk file, others may be able to read standard input; similar for
@@ -264,7 +264,7 @@
# Reliably quote a string as a single argument for /bin/sh
-_safechars = string.letters + string.digits + '!@%_-+=:,./' # Safe unquoted
+_safechars = string.ascii_letters + string.digits + '!@%_-+=:,./' # Safe unquoted
_funnychars = '"`$\\' # Unsafe inside "double quotes"
def quote(file):