Plugin approx: migrate to Python3, format documentation

plugins/apt/approx

@@ -1,23 +1,32 @@
-#!/usr/bin/env python
-#
-# vim:syntax=python
-#
-# Plugin to monitor the amount of packages in an approx cache.
-#
-# Usage: place in /etc/munin/plugins/ (or link it there using ln -s)
-#
-# Parameters understood:
-#
-#     config   (required)
-#     autoconf (optional - used by munin-config)
-#
-# Magic markers - optional - used by installation scripts and
-# munin-config:
-#
-#  #%# family=manual
-#  #%# capabilities=autoconf
-#
-# Now for the real work...
+#!/usr/bin/env python3
+"""
+=head1 NAME
+
+approx - monitor the amount of packages in an approx cache
+
+
+=head1 CONFIGURATION
+
+Usage: place in /etc/munin/plugins/ (or link it there using ln -s)
+
+Parameters understood:
+
+ config   (required)
+ autoconf (optional - used by munin-config)
+
+
+=head1 AUTHORS
+
+Copyright 2008 Morten Siebuhr <unknown@munin-monitoring.org>
+
+
+=head1 MAGIC MARKERS
+
+ #%# family=manual
+ #%# capabilities=autoconf
+
+=cut
+"""
 
 from os.path import walk, exists, isfile, join
 from sys import argv, exit
@@ -58,7 +67,7 @@ if len(argv) > 1:
             print("%s.label %s" % (filetype.lower(), filetype))
         exit()
 
-for filetype, count in get_file_types().iteritems():
+for filetype, count in get_file_types().items():
     print("%s.value %d" % (filetype.lower(), count))
 
 exit()