function isRegExp(value) {
      return isObject(value) && objectToString.call(value) == regexpTag;
    }
Checks if `value` is classified as a `RegExp` object.

@static
@memberOf _
@since 0.1.0
@category Lang
@param {*} value The value to check.
@returns {boolean} Returns `true` if `value` is correctly classified,
 else `false`.
@example

_.isRegExp(/abc/);
// => true

_.isRegExp('/abc/');
// => false