function isDate(value) {
      return (value && typeof value == 'object' && toString.call(value) == dateClass) || false;
    }
Checks if `value` is classified as a `Date` object.

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

_.isDate(new Date);
// => true

_.isDate('Mon April 23 2012');
// => false