[Bug] occur a reference error when using it with flask_socketio

Describe the bug

When I import TTS module to my app.py(see the reproduce code), It will occur a reference error. When I don't import the TTS module, it can work well. I just want to use the flask_socketio to build a service to convert text to speech.

To Reproduce

the minimal reproducible code

from flask import Flask
from flask_socketio import SocketIO
import logging
from TTS.api import TTS

def create_app():
    app = Flask(__name__)
    return app

app = create_app()
socketio = SocketIO(
    app,
    path="/socket.io",
    cors_allowed_origins="*",
    logger=True,
    engineio_logger=True,
)

if __name__ == "__main__":
    host = "0.0.0.0"
    port = 8172
    app.logger.info(f"server listen on http://{host}:{port}")
    socketio.run(app, host, port, debug=True)

run this code
you can see the error

requirements.txt

Flask==3.0.3
Requests==2.32.3
gevent==24.2.1
Flask-SocketIO==5.3.6
gevent-websocket==0.10.1
TTS==0.22.0

Expected behavior

No error. It can run successful.

Logs

No response

Environment

- 🐸TTS Version (e.g., 1.3.0): 0.22.0
- PyTorch Version (e.g., 1.8): 2.4.0
- Python version: 3.9.19
- OS (e.g., Linux): Mac OS 14.5
- CUDA/cuDNN version: 
- GPU models and configuration: 
- How you installed PyTorch (`conda`, `pip`, source): pip
- Any other relevant information:

the JSON by collect_env_info.py

{
    "CUDA": {
        "GPU": [],
        "available": false,
        "version": null
    },
    "Packages": {
        "PyTorch_debug": false,
        "PyTorch_version": "2.4.0",
        "TTS": "0.22.0",
        "numpy": "1.22.0"
    },
    "System": {
        "OS": "Darwin",
        "architecture": [
            "64bit",
            ""
        ],
        "processor": "arm",
        "python": "3.9.19",
        "version": "Darwin Kernel Version 23.5.0: Wed May  1 20:12:58 PDT 2024; root:xnu-10063.121.3~5/RELEASE_ARM64_T6000"
    }
}

Additional context