California Commercial Code Section 10515

(a) Acceptance of goods occurs after the lessee has had a reasonable opportunity to inspect the goods and (1) The lessee signifies or acts with respect to the goods in a manner that signifies to the lessor or the supplier that the goods are conforming or that the lessee will take or retain them in spite of their nonconformity; or (2) The lessee fails to make an effective rejection of the goods (subdivision (b) of Section 10509). (b) Acceptance of a part of any commercial unit is acceptance of that entire unit.