In a partnership, when a new partner is being admitted into the partnership, is the consent of creditor necessary for the admission to be valid? and if the incoming partner agreed to accept the liabilities incurred by the firm before he joined the firm, if there is an agreement reached between the creditor , the old partners and the incoming partner rather than just an agreement between partners, would the creditor have the right to sue the new partner or he would still have no right against the incoming partner?