n1 Kenneth contends the judgment was also correct on the ground Doris's retention of money in the reserve fund would amount to usury. The trial judge expressly declined to address this point, since the judge concluded the lease did not give Doris the right to retain any of that money. For the same reason, we need not decide the usury issue on appeal. Kenneth also requests sanctions on the ground the appeal is frivolous. Sanctions are inappropriate. The dispositive equitable principles in this case, though ancient, are too complex for us to conclude that no reasonable attorney would have prosecuted the appeal. (See In re Marriage of Flaherty (1982) 31 Cal.3d 637, 650 [183 Cal.Rptr. 508, 646 P.2d 179].)