function isFunction(value) {
	  // The use of `Object#toString` avoids issues with the `typeof` operator
	  // in Safari 8 which returns 'object' for typed array and weak map constructors,
	  // and PhantomJS 1.9 which returns 'function' for `NodeList` instances.
	  var tag = isObject(value) ? objectToString.call(value) : '';
	  return tag == funcTag || tag == genTag;
	}
Checks if `value` is classified as a `Function` 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

_.isFunction(_);
// => true

_.isFunction(/abc/);
// => false