human
Complete the below
def env(a, import_models=False, c=None, f=None, dir='', extra_request={}):

    ''''Returns web2py execution environment for application (a), controller (c),
    function (f).
    If import_models is True the exec all application models into the
    environment.
    extra_request allows you to pass along any extra variables to the request
    object before your models get executed. This was mainly done to support
    web2py_utils.test_runner, however you can use it with any wrapper scripts
    that need access to the web2py environment.'
    '''
 Write me a the Python code you requested?
assistant
#Here is the Python code you requested.
    request = Request({})
    response = Response()
    session = Session()
    request.application = a
    if (not dir):
        request.folder = os.path.join('applications', a)
    else:
        request.folder = dir
    request.controller = (c or 'default')
    request.function = (f or 'index')
    response.view = ('%s/%s.html' % (request.controller, request.function))
    if global_settings.cmd_options:
        ip = global_settings.cmd_options.ip
        port = global_settings.cmd_options.port
        request.is_shell = (global_settings.cmd_options.shell is not None)
        request.is_scheduler = (global_settings.cmd_options.scheduler is not None)
    else:
        (ip, port) = ('127.0.0.1', '8000')
    request.env.http_host = ('%s:%s' % (ip, port))
    request.env.remote_addr = '127.0.0.1'
    request.env.web2py_runtime_gae = global_settings.web2py_runtime_gae
    for (k, v) in extra_request.items():
        request[k] = v
    path_info = ('/%s/%s/%s' % (a, c, f))
    if request.args:
        path_info = ('%s/%s' % (path_info, '/'.join(request.args)))
    if request.vars:
        vars = [(('%s=%s' % (k, v)) if v else ('%s' % k)) for (k, v) in iteritems(request.vars)]
        path_info = ('%s?%s' % (path_info, '&'.join(vars)))
    request.env.path_info = path_info
    def check_credentials(request, other_application='admin'):
        return True
    fileutils.check_credentials = check_credentials
    environment = build_environment(request, response, session)
    if import_models:
        try:
            run_models_in(environment)
        except RestrictedError as e:
            sys.stderr.write((e.traceback + '\n'))
            sys.exit(1)
    response._view_environment = copy.copy(environment)
    environment['__name__'] = '__main__'
    return environment