Walker & Co. contracted to provide a sign for Harrison to place above his dry cleaning business. According to the contract, Harrison would lease the sign from Walker, making monthly payments for thirty-six months. In return, Walker agreed to maintain and service the sign at its own expense. Walker installed the sign in July, and Harrison made the first rental payment. Shortly thereafter, someone hit the sign with a tomato. Harrison also claims he discovered rust on its chrome and little spider webs in its corners. Harrison repeatedly called Walker for the maintenance work promised under the contract, but Walker did not respond immediately. Harrison then telegraphed Walker that due to Walker’s failure to perform the maintenance services, he held Walker in material breach of the contract. A week later, Walker sent out a crew, which did all of the requested maintenance services. Has Walker committed a material breach of contract? Explain.