Document CashFlowDirection

class CashFlowDirection(Enum):

    """The direction in which money flows.

    It can either be income (CashFlowDirection.INCOMING) or expenses (CashFlowDirection.OUTGOING).

    When no further information is given, the cash flow direction is determined from the perspective

    of the Fachschaft (e.g., CashFlowDirection.OUTGOING would be assigned if the Fachschaft buys

    something from a seller, even though for the seller this would of course be income).

    CashFlowDirection.INCOMING.value and CashFlowDirection.OUTGOING.value are 1 and -1, respectively,

    and can be used to build a weighted sum to calculate total profit.

    """

    INCOMING = 1

    OUTGOING = -1