if list._tail == m then

		list._tail = m.prev;

	if list._head == m then

		list._head = m.next;

	list._count = list._count - 1;

	if list._head then

		list._head.prev = m;

	m.prev, m.next = nil, list._head;

	list._head = m;

	if not list._tail then

		list._tail = m;

	list._count = list._count + 1;

local cache_methods = {};

local cache_mt = { __index = cache_methods };

	local m = self._data[k];

			self._data[k] = nil;

		return true;

		return true;

	if self._count == self.size then

		local tail = self._tail;

		local on_evict = self._on_evict;

		if on_evict then

			on_evict(tail.key, tail.value);

		end

		_remove(self, tail);

		self._data[tail.key] = nil;

	self._data[k] = m;

	return true;

	local m = self._data[k];

	local m = self._head;

function cache_methods:count()

	return self._count;

end

local function new(size, on_evict)

	size = assert(tonumber(size), "cache size must be a number");

	size = math.floor(size);

	assert(size > 0, "cache size must be greater than zero");

	local data = {};

	return setmetatable({ _data = data, _count = 0, size = size, _head = nil, _tail = nil, _on_evict = on_evict }, cache_mt);

end