我正在尝试部署Zappa应用程序，以便使用Python将AWS RDS连接到PostgreSQL。当我们从终端的代码执行时，代码运行良好，RDS连接到PostgreSQL。但当我尝试在Zappa中执行代码时，它抛出以下错误：

错误：警告！对已部署的lambda进行状态检查失败。对‘/’的GET请求产生502响应代码。
zappa_settings.json文件如下：

"dev": {
        "app_function": "app.app",
        "aws_region": "ap-south-1",
        "profile_name": "default",
        "project_name": "rds-postgres-py",
        "runtime": "python3.8",
        "s3_bucket": "zappa-aoxdyg89v"
    }
}

使用Zappa Tail的部署日志如下：

[1665576386682] [DEBUG] 2022-10-12T12:06:26.682Z 662d3c73-766e-45ec-87c4-d9caeeb9a143 Zappa Event: {'time': '2022-10-12T12:06:08Z', 'detail-type': 'Scheduled Event', 'source': 'aws.events', 'account': '891890779389', 'region': 'ap-south-1', 'detail': {}, 'version': '0', 'resources': ['arn:aws:events:ap-south-1:891890779389:rule/rds-postgres-py-dev-zappa-keep-warm-handler.keep_warm_callback'], 'id': '32e22a30-3a4f-07c0-9613-c523351b5484', 'kwargs': {}}
[1665576386682] [DEBUG] 2022-10-12T12:06:26.682Z 662d3c73-766e-45ec-87c4-d9caeeb9a143 Zappa Event: {}
[1665576404722] Instancing..
[1665576404724] [ERROR] ModuleNotFoundError: No module named 'app'
Traceback (most recent call last):
  File "/var/task/handler.py", line 625, in lambda_handler
    return LambdaHandler.lambda_handler(event, context)
  File "/var/task/handler.py", line 240, in lambda_handler
    handler = global_handler or cls()
  File "/var/task/handler.py", line 137, in __init__
    self.app_module = importlib.import_module(self.settings.APP_MODULE)
  File "/var/lang/lib/python3.8/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1014, in _gcd_import
  File "<frozen importlib._bootstrap>", line 991, in _find_and_load
  File "<frozen importlib._bootstrap>", line 973, in _find_and_load_unlocked

在日志文件中，**[Error]ModuleNotFoundError：没有生成名为‘app’**的模块。但是我有app.py，这是我编写代码的地方。
该文件的结构为：

|__RDS_Postgres_Zappa 
     |__ virtual_env 
     |__src     
     │  ├── __init__.py
     │  └── app.py
     │  └── database.ini
     └── zappa_settings.json

Python版本为Python3.8，Zappa版本为0.55.0
我不知道哪里出了问题。