Black supports attribute access and call chaining to provide good formatting for fluent interface style programming with extensive method chaining which is common e.g. with django (https://black.readthedocs.io/en/stable/the_black_code_style/current_style.html#call-chains):

def example(session):
    result = (
        session.query(models.Customer.id)
        .filter(
            models.Customer.account_id == account_id,
            models.Customer.email == email_address,
        )
        .order_by(models.Customer.id.asc())
        .all()
    )

#5340 implements a part of this badly to fix a bug and #5341 adds basic function call formatting.

We need to implement a formatting where the outermost call adds the optional parentheses and formats all inner accesses and calls to not have them add parentheses. A complication is that unlike for if-statements the tree is left recursive, meaning that for a.b().c.d.e the outermost call see an access of e on a.b().c.d, while we must format first a, then .b(), .d and finally .e. We can implement by either collecting into a stack (needs allocation) or using recursing (we most not overrun the recursion and stack limits).