28663 family law/ common property/ sale/ contract law property law contract law family law common property Federal supreme court of Ethiopia cassation decisions contract of sale volume 7 የፍ/ብ/ህ/ቁ. 658 ተጋቢ ወገን ከሦስተኛ ወገን ጋር ያደረገውን ውል ለማፍረስ ምክንያት ስላለመሆኑ የፍ/ብ/ህ/ቁ. 658, 686Cassation Decision no. 28663