diff --git a/bumblebee/config.py b/bumblebee/config.py
index ef7a4c7..43a1e93 100644
--- a/bumblebee/config.py
+++ b/bumblebee/config.py
@@ -5,11 +5,41 @@ import textwrap
 import bumblebee.theme
 import bumblebee.module
 
+class print_usage(argparse.Action):
+    def __init__(self, option_strings, dest, nargs=None, **kwargs):
+        argparse.Action.__init__(self, option_strings, dest, nargs, **kwargs)
+        self._indent = " "*4
+
+    def __call__(self, parser, namespace, value, option_string=None):
+        if value == "modules":
+            self.print_modules()
+        elif value == "themes":
+            self.print_themes()
+        else:
+            parser.print_help()
+        parser.exit()
+
+    def print_themes(self):
+        print(textwrap.fill(", ".join(bumblebee.theme.themes()),
+            80, initial_indent = self._indent, subsequent_indent = self._indent
+        ))
+
+    def print_modules(self):
+        for m in bumblebee.module.modules():
+
+            print("{}{}: ".format(self._indent, m.name()))
+            print textwrap.fill("About : {}".format(m.description()),
+                80, initial_indent=self._indent*2, subsequent_indent=self._indent*4)
+            print textwrap.fill("Usage : {}".format(m.usage()),
+                80, initial_indent=self._indent*2, subsequent_indent=self._indent*4)
+            print textwrap.fill("Notes : {}".format(m.notes()),
+                80, initial_indent=self._indent*2, subsequent_indent=self._indent*4)
+            print ""
+
 class Config(object):
     def __init__(self, args):
         self._raw = args
         self._parser = self._parser()
-        self._indent = " "*4
         self._store = {}
 
         if len(args) == 0:
@@ -18,13 +48,6 @@ class Config(object):
 
         self._args = self._parser.parse_args(args)
 
-        if self._args.list == "modules":
-            self.print_modules()
-        if self._args.list == "themes":
-            self.print_themes()
-        if self._args.list:
-            self._parser.exit()
-
     def getstore(self, name, default=None):
         if not name in self._store:
             self._store[name] = default
@@ -49,22 +72,6 @@ class Config(object):
     def modules(self):
         return self._args.modules
 
-    def print_themes(self):
-        print(textwrap.fill(", ".join(bumblebee.theme.themes()),
-            80, initial_indent = self._indent, subsequent_indent = self._indent
-        ))
-
-    def print_modules(self):
-        for m in bumblebee.module.modules():
-
-            print("{}{}: ".format(self._indent, m.name()))
-            print textwrap.fill("About : {}".format(m.description()),
-                80, initial_indent=self._indent*2, subsequent_indent=self._indent*4)
-            print textwrap.fill("Usage : {}".format(m.usage()),
-                80, initial_indent=self._indent*2, subsequent_indent=self._indent*4)
-            print textwrap.fill("Notes : {}".format(m.notes()),
-                80, initial_indent=self._indent*2, subsequent_indent=self._indent*4)
-            print ""
 
     def _parser(self):
         parser = argparse.ArgumentParser(description="display system data in the i3bar")
@@ -76,6 +83,7 @@ class Config(object):
         parser.add_argument("-l", "--list",
             help="List: 'modules', 'themes' ",
             choices = [ "modules", "themes" ],
+            action=print_usage,
         )
         parser.add_argument("-t", "--theme", help="Specify which theme to use for "
             "drawing the modules",
@@ -84,5 +92,4 @@ class Config(object):
 
         return parser
 
-
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