Fixed encode()/decode() turn-around.

pep-3137.txt

@@ -230,9 +230,9 @@ should just return False).
 Conversions between bytes or buffer objects and str objects must
 always be explicit, using an encoding.  There are two equivalent APIs:
 ``str(b, <encoding>[, <errors>])`` is equivalent to
-``b.encode(<encoding>[, <errors>])``, and
+``b.decode(<encoding>[, <errors>])``, and
 ``bytes(s, <encoding>[, <errors>])`` is equivalent to
-``s.decode(<encoding>[, <errors>])``.
+``s.encode(<encoding>[, <errors>])``.
   
 There is one exception: we can convert from bytes (or buffer) to str
 without specifying an encoding by writing ``str(b)``.  This produces