code: function _addMethod(methodDictionary, func, name) {
    expect(func).to.be.a(
      'function',
      'Invalid argument "func" when adding a method called "' + name + '" in a ' +
      'MethodDictionary (it has to be a function)'
    );
  
    Object.defineProperty(methodDictionary, name, {
      value: func,
      enumerable: true,
      writable: false,
      configurable: false
    });
  }
docs: Adds a new method to the dictionary.
  @name module:back4app-entity/models/methods~_addMethod
  @function
  @param {!module:back4app-entity/models/methods.MethodDictionary}
  methodDictionary This is the MethodDictionary instance to which the method
  will be added.
  @param {!function} func This is the method's function to be added.
  @param {!string} name This is the name of the method.
  @private
  @example
  MethodDictionary.add(
  methodDictionary,
  function () { return 'method3'; },
  'method3'
  );