_.isWeakMap(value)

_.isNil(value) source

_.mergeWith(object, sources, customizer)

_.stubObject() source

_.forEachRight(collection, [iteratee=_.identity])

_.assignWith(object, sources, [customizer])

_.dropRight(array, [n=1])

_.flattenDeep(array)

_.updateWith(object, path, updater, [customizer])

_.overArgs(func, [transforms=[_.identity]])