<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def init(scope, app, settings):
 """Plugin for serving static files in development mode"""

    cfg = settings.get('rw.static', {})
    static = Static()
    scope['static'] = static
    scope['template_env'].globals['static'] = static
    for base_uri, sources in cfg.items():
        full_paths = []
        for source in sources:
            if isinstance(source, dict):
                full_path = source['path']
                full_paths.append(full_path.format(**os.environ))
                continue
            elif ',' in source:
                module_name, path = [part.strip()
                                     for part in source.split(',')]
            else:
                module_name = source
                path = 'static'
            full_path = pkg_resources.resource_filename(module_name, path)
            full_paths.append(full_path)

        app.root.mount('/' + base_uri + '/<h>/<path:path>',
                       StaticHandler, {'path': full_paths},
                       name='static_' + base_uri.replace('.', '_'))

        static.handlers.append((base_uri, StaticHandler, full_paths))
    static.setup()