Where a county public defender has refused, or is otherwise reasonably unable, to represent a person because of conflict of interest or other reason, the State Public Defender is authorized to represent that person, pursuant to a contract with the county which provides for reimbursement of costs, where the person is not financially able to employ counsel and is charged with the commission of any contempt or offense triable in the superior court at all stages of any proceedings relating to that charge, including restrictions on liberty resulting from that charge. The State Public Defender may decline to represent the person by filing a letter with the appropriate court citing Section 15420.