abuse python decorators + default mutable args

evil.py

import functools
import datetime as dt

def capture():
  def decorator(func):
    @functools.wraps(func)
    def wrapper(*args, ctx=[], **kwargs):
      if len(ctx) > 0:
        print(f"this function was last called at {ctx[-1][0]}")
      ctx.append((dt.datetime.now(), args, kwargs))

      return func(*args, **kwargs)

    return wrapper

  return decorator

@capture()
def add(x, y):
  return x+y