code: function MethodDictionary(methods) {
    expect(arguments).to.have.length.below(
      2,
      'Invalid arguments length when creating a new MethodDictionary (it has ' +
      'to be passed less than 2 arguments)'
    );
  
    if (methods) {
      expect(methods).to.be.an(
        'object',
        'Invalid argument type when creating a new MethodDictionary (it has to ' +
        'be an object)'
      );
  
      for (var method in methods) {
        _addMethod(this, methods[method], method);
      }
    }
  
    Object.preventExtensions(this);
    Object.seal(this);
  }
docs: Dictionary of Entity Methods. An instance of MethodDictionary is not
  extensible.
  @constructor
  @memberof module:back4app-entity/models/methods
  @param {?Object.<!string, !function>} [methods] The methods to be added in
  the dictionary. They have to be given as a dictionary of functions.
  @example
  var methodDictionary = new MethodDictionary();
  @example
  var methodDictionary = new MethodDictionary(null);
  @example
  var methodDictionary = new MethodDictionary({});
  @example
  var methodDictionary = new MethodDictionary({
  method1: function () { return 'method1'; },
  method2: function () { return 'method2'; }
  });