function isObject(value) {
      var type = typeof value;
      return value != null && (type == 'object' || type == 'function');
    }
Checks if `value` is classified as a `Map` object.

@static
@memberOf _
@since 4.3.0
@category Lang
@param {*} value The value to check.
@returns {boolean} Returns `true` if `value` is a map, else `false`.
@example

_.isMap(new Map);
// => true

_.isMap(new WeakMap);
// => false