diff --git a/Lib/urlparse.py b/Lib/urlparse.py
index 1d065d3..f6e20af 100644
--- a/Lib/urlparse.py
+++ b/Lib/urlparse.py
@@ -272,8 +272,9 @@
 # Cannot use directly from urllib as it would create circular reference.
 # urllib uses urlparse methods ( urljoin)
 
-_hextochr = dict(('%02x' % i, chr(i)) for i in range(256))
-_hextochr.update(('%02X' % i, chr(i)) for i in range(256))
+
+_hexdig = '0123456789ABCDEFabcdef'
+_hextochr = dict((a+b, chr(int(a+b,16))) for a in _hexdig for b in _hexdig)
 
 def unquote(s):
     """unquote('abc%20def') -> 'abc def'."""