l</span> fold_last : <span><span class="type-var">'a</span> list</span> <span>&#45;&gt;</span> <span>init:<span class="type-var">'b</span></span> <span>&#45;&gt;</span> <span>f:<span>(<span class="type-var">'b</span> <span>&#45;&gt;</span> <span class="type-var">'a</span> <span>&#45;&gt;</span> <span class="type-var">'b</span>)</span></span> <span>&#45;&gt;</span> <span>f_last:<span>(<span class="type-var">'b</span> <span>&#45;&gt;</span> <span class="type-var">'a</span> <span>&#45;&gt;</span> <span class="