cached dataframe that's immutable

cached_dataframe.py

import functools
import time
from typing import Any, Callable

import pandas


def df_cache(f: Callable[..., Any]) -> Callable[..., Any]:
    functools.wraps(f)

    def wrapper(*args: Any, **kwargs: Any) -> Any:
        print("before")
        return f(*args, **kwargs)
    return wrapper


@functools.lru_cache(1)
def long_method() -> pandas.DataFrame:
    time.sleep(3)
    return pandas.DataFrame([3])


@df_cache
def hoge() -> pandas.DataFrame:
    return long_method().copy()


df = hoge()
df.iloc[0, 0] += 1
print(df)
print(hoge())