def get_installed_pypackages():
    return {p.project_name.lower(): p for p in pkg_resources.working_set}
def draw(self, context):
        layout = self.layout

        layout.template_header()

        userpref = context.user_preferences

        layout.operator_context = 'EXEC_AREA'
        layout.operator("wm.save_userpref")

        layout.operator_context = 'INVOKE_DEFAULT'

        if userpref.active_section == 'INPUT':
            layout.operator("wm.keyconfig_import")
            layout.operator("wm.keyconfig_export")
        elif userpref.active_section == 'ADDONS':
            layout.operator("wm.addon_install", icon='FILESEL')
            layout.operator("wm.addon_refresh", icon='FILE_REFRESH')
            layout.menu("USERPREF_MT_addons_online_resources")
        elif userpref.active_section == 'THEMES':
            layout.operator("ui.reset_default_theme")
            layout.operator("wm.theme_install")