def get_dividend_sum(book: Book, income_account: Account):
    """    Adds all distributions (income)    """
    splits = book.session.query(Split).filter(Split.account == income_account).all()
    dividend_sum = Decimal(0)

    for split in splits:
        dividend_sum += split.value
        # debug print split...

    # Since the income comes from the distribution account, it is marked as debit.
    return dividend_sum * (-1)