[Feature Request] Can we have template for code generation?

Hi! thanks for making the great database!
I'm happily learning edgedb nowdays. 😆

can we have template for code generation?

## example

below edgeql generates below python code
```edgeql
select 1;
```

```py
# AUTOGENERATED FROM 'app/queries/test.edgeql' WITH:
# $ edgedb-py

from __future__ import annotations
import edgedb

async def test(
executor: edgedb.AsyncIOExecutor,
) -> int:
return await executor.query_single(
"""\
select 1;\
""",
)
```

but this code doesn't pass strict mypy check since query_single is returning `Any`.

## cast?

I want to use `typing.cast()` to pass mypy check

```py
return cast(int, await executor.query_single(
"""\
select 1;\
""",
))
```

how do I achieve this? 🤔