A homeowner hired a contractor to finish her basement. They agreed on a price of $20,000 for the job. During the final stages of the remodeling, the contractor discovered that there was mold in the basement, the existence of which had been unknown to either party. The contractor refused to complete the job unless the homeowner paid an additional $2,000 to the contractor for removal of the mold. The homeowner reluctantly agreed, and the contractor finished the basement in accord with the modified contract. The homeowner paid the contractor $20,000. In a breach of contract action to recover the $2,000, will the contractor prevail?