code: function isDirty(attribute) {
      expect(arguments).to.have.length.below(
        2,
        'Invalid arguments length when checking if an Entity attribute is ' +
        'dirty (it has to be passed less than 2 arguments)'
      );
  
      var attributes = this.Entity.attributes;
  
      if (attribute) {
        expect(attribute).to.be.a(
          'string',
          'Invalid argument "attribute" when checking if an Entity attribute ' +
          'is dirty (it has to be a string)'
        );
  
        expect(attributes).to.have.ownProperty(
          attribute,
          'Invalid argument "attribute" when checking an Entity attribute ' +
          'is dirty (this attribute does not exist in the Entity)'
        );
  
        var newAttributes = {};
        newAttributes[attribute] = attributes[attribute];
        attributes = newAttributes;
      }
  
      if (this.isNew) {
        return true;
      }
  
      for (var attributeName in attributes) {
        if (_cleanSet) {
          if (_attributeIsSet[attributeName]) {
            if (
              !_attributeStorageValues.hasOwnProperty(attributeName) ||
              _attributeStorageValues[attributeName] !== this[attributeName]
            ) {
              return true;
            }
          }
        } else {
          if (
            !_attributeStorageValues.hasOwnProperty(attributeName) ||
            _attributeStorageValues[attributeName] !== this[attributeName]
          ) {
            return true;
          }
        }
      }
  
      return false;
    }
docs: Checks if an Entity attribute is dirty.
  @name module:back4app-entity/models.Entity#isDirty
  @function
  @param {?string} [attribute] The name of the attribute to be checked. If no
  attribute is passed, all attributes will be checked.
  @returns {boolean} True if is dirty and false otherwise.
  @example
  console.log(myEntity.isDirty('myAttribute')); // Validates attribute
  // "myAttribute" of
  // Entity "myEntity"
  @example
  console.log(myEntity.isDirty()); // Checks all attributes of "myEntity"