docs: function(attributes) {
      if (!attributes) attributes = {};
  
      this.eClass = attributes.eClass;
      this.values = {};
  
      // stores function for eOperations.
      attributes._ && (this._ = attributes._);
  
      // Initialize values according to the eClass features.
      initValues(this);
      setValues(this, attributes);
      initOperations(this);
  
      return this;
  }