system: You are an expert security code reviewer. You will be shown a source code file. Your task is to name the single function or class that contains the specified CWE vulnerability.

OUTPUT FORMAT: Respond with the exact function or class name (no parentheses, no qualifiers, no module prefixes), wrapped in \boxed{...}. Example: `\boxed{salted_hmac}`. Output the boxed name ONLY -- no explanation, no other text.

user: ```python
import os
import flask
import flask_sqlalchemy
import flask_praetorian
import flask_cors
from quickey_python_sdk import sdk


db = flask_sqlalchemy.SQLAlchemy()
guard = flask_praetorian.Praetorian()
cors = flask_cors.CORS()

# A generic user model that might be used by an app powered by flask-praetorian
class User(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.Text, unique=True)
    password = db.Column(db.Text)
    roles = db.Column(db.Text)
    is_active = db.Column(db.Boolean, default=True, server_default='true')

    @property
    def rolenames(self):
        try:
            return self.roles.split(',')
        except Exception:
            return []

    @classmethod
    def lookup(cls, username):
        return cls.query.filter_by(username=username).one_or_none()

    @classmethod
    def identify(cls, id):
        return cls.query.get(id)

    @property
    def identity(self):
        return self.id

    def is_valid(self):
        return self.is_active


# Initialize flask app for the example
app = flask.Flask(__name__, static_folder='../build', static_url_path=None)
app.debug = True
app.config['SECRET_KEY'] = 'top secret'
app.config['JWT_ACCESS_LIFESPAN'] = {'hours': 24}
app.config['JWT_REFRESH_LIFESPAN'] = {'days': 30}

# Initialize the flask-praetorian instance for the app
guard.init_app(app, User)

# Initialize a local database for the example
app.config['SQLALCHEMY_DATABASE_URI'] = f"sqlite:///{os.path.join(os.getcwd(), 'database.db')}"
db.init_app(app)

# Initializes CORS so that the api_tool can talk to the example app
cors.init_app(app)

# Add users for the example
with app.app_context():
    db.create_all()
    if db.session.query(User).filter_by(username='efrizal').count() < 1:
        db.session.add(User(
          username='efrizal',
          password=guard.hash_password('123'),
          roles='admin'
		))
    db.session.commit()


# Set up some routes for the example
@app.route('/api/')
def home():
    return {"Hello": "World"}, 200

@app.route('/api/login', methods=['POST'])
def login():
    # app = sdk.App('inT9Ic-BhfqbRA-wgtz8Dn_WHUuAAmSI3VN0kByQpyU').getAppMetaData()
    # email = app.json()['app']['email']
    # print(email)
    req = flask.request.get_json(force=True)
    provider = req.get('provider', None)
    if provider:
        app = sdk.Auth().getAccessToken('efrizal@analisa.io')
        access_token = app.json()['access_token']
        # user = guard.authenticate(username, password)
        ret = {'access_token': access_token}
        return ret, 200
    else:
        username = req.get('username', None)
        password = req.get('password', None)
        user = guard.authenticate(username, password)
        ret = {'access_token': guard.encode_jwt_token(user)}
        return ret, 200

@app.route('/api/refresh', methods=['POST'])
def refresh():
    print("refresh request")
    old_token = requests.get_data()
    new_token = guard.refresh_jwt_token(old_token)
    ret = {'access_token': new_token}
    return ret, 200


@app.route('/api/protected')
@flask_praetorian.auth_required
def protected():
    """
    A protected endpoint. The auth_required decorator will require a header
    containing a valid JWT
    .. example::
       $ curl http://localhost:5000/api/protected -X GET \
         -H "Authorization: Bearer <your_token>"
    """
    return {"message": f'protected endpoint (allowed user {flask_praetorian.current_user().username})'}


@app.route('/', defaults={'path': ''})
@app.route('/<path:path>')
def catch_all(path):
    print("Hello from catch all")
    if path != "" and os.path.exists(os.path.join('..','build',path)):
        return app.send_static_file(path)
    else:
        return app.send_static_file('index.html')

# Run the example
if __name__ == '__main__':
    app.run(host='0.0.0.0', port=5000)
```

Name the function or class in this code that contains a `CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')` vulnerability.
Answer: catch_all