Updated the rules for package names and module names, clarifying the use of

underscores.

pep-0008.txt

@@ -468,9 +468,12 @@ Naming Conventions
       In some fonts, these characters are indistinguishable from the numerals
       one and zero.  When tempted to use `l', use `L' instead.
 
-    Module Names
+    Package and Module Names
 
-      Modules should have short, lowercase names, without underscores.
+      Modules should have short, all-lowercase names.  Underscores can be used
+      in the module name if it improves readability.  Python packages should
+      also have short, all-lowercase names, although the use of underscores is
+      discouraged.
 
       Since module names are mapped to file names, and some file systems are
       case insensitive and truncate long names, it is important that module
@@ -482,9 +485,6 @@ Naming Conventions
       module that provides a higher level (e.g. more object oriented)
       interface, the C/C++ module has a leading underscore (e.g. _socket).
 
-      Like modules, Python packages should have short, all-lowercase names,
-      without underscores.
-
     Class Names
 
       Almost without exception, class names use the CapWords convention.