In this Act "housing trust" means a corporation or body of persons which—
is required by the terms of its constituent instrument to use the whole of its funds, including any surplus which may arise from its operations, for the purpose of providing housing accommodation, or
is required by the terms of its constituent instrument to devote the whole, or substantially the whole, of its funds for charitable purposes and in fact uses the whole, or substantially the whole, of its funds for the purpose of providing housing accommodation.