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 such 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 such charge, including restrictions on liberty resulting from such
charge. Except in cases of representation under subdivision (d) of Section 15421, the State Public Defender may decline to represent such person by filing a letter with the appropriate court citing Section 15420 of this chapter.