Plaintiffs leased commercial space from the defendant to open a florist shop. After the lease was executed, the plaintiffs learned that they could not place a freestanding sign along the highway to advertise their business because the Deschutes County Code allowed only one freestanding sign on the property, and the defendant already had one in place. The plaintiffs filed this action, alleging that defendant had breached the lease by failing to provide them with space in which they could erect a freestanding sign. Paragraph 16 of the lease provides as follows: ‘‘Tenant shall not erect or install any signs visible from outside the leased premises with out [sic] the previous written consent of the Landlord.’’ Explain whether this evidence is admissible.