function isNull(value) {
      return value === null;
    }
Checks if `value` is `null`.

@static
@memberOf _
@category Lang
@param {*} value The value to check.
@returns {boolean} Returns `true` if `value` is `null`, else `false`.
@example

_.isNull(null);
// => true

_.isNull(void 0);
// => false