I'm a big fan of functional programming but this documentation is kind of funny, unintentionally. I realize there is no better way to do it in Python.

And that’s how your initial refactored code will look like:

  user: Optional[User]

  can_buy_stuff: Maybe[bool] = Maybe.from_value(user).map(  # type hint is not required
      lambda real_user: real_user.get_balance(),
  ).map(
      lambda balance: balance.credit_amount(),
  ).map(
      lambda balance_credit: balance_credit > 0,
  )

Much better, isn’t it?