\section{\module{pkgutil} ---         Package extension utility} \declaremodule{standard}{pkgutil}\modulesynopsis{Utilities to support extension of packages.} \versionadded{2.3} This module provides a single function: \begin{funcdesc}{extend_path}{path, name}  Extend the search path for the modules which comprise a package.  Intended use is to place the following code in a package's  \file{__init__.py}: \begin{verbatim}from pkgutil import extend_path__path__ = extend_path(__path__, __name__)\end{verbatim}   This will add to the package's \code{__path__} all subdirectories of  directories on \code{sys.path} named after the package.  This is  useful if one wants to distribute different parts of a single  logical package as multiple directories.   It also looks for \file{*.pkg} files beginning where \code{*}  matches the \var{name} argument.  This feature is similar to  \file{*.pth} files (see the \refmodule{site} module for more  information), except that it doesn't special-case lines starting  with \code{import}.  A \file{*.pkg} file is trusted at face value:  apart from checking for duplicates, all entries found in a  \file{*.pkg} file are added to the path, regardless of whether they  exist on the filesystem.  (This is a feature.)   If the input path is not a list (as is the case for frozen  packages) it is returned unchanged.  The input path is not  modified; an extended copy is returned.  Items are only appended  to the copy at the end.   It is assumed that \code{sys.path} is a sequence.  Items of  \code{sys.path} that are not (Unicode or 8-bit) strings referring to  existing directories are ignored.  Unicode items on \code{sys.path}  that cause errors when used as filenames may cause this function to  raise an exception (in line with \function{os.path.isdir()} behavior).\end{funcdesc}