how about Now.sh?

now.json

{
  "version": 2,
  "name": "my-python-project",
  "builds": [
    { "src": "www/**/*", "use": "@now/static" },
    { "src": "api/**/*.py", "use": "@now/python" }
  ],
  "routes": [
    {
      "src": "/",
      "dest": "www/index.html"
    },
    {
      "src": "^/api/(function|function\\.py)$",
      "dest": "api/function.py"
    },
    {
      "status": 404,
      "src": "/api(\\/.*)?$"
    }
  ]
}

tree.txt

public
├── api
│   ├── function.py
│   └── requirements.txt
├── now.json
└── www
    └── index.html