code: function( key ) {
  
      if( this.data[ key ] == null ) {
        return this.data[ key ]
      }
  
      if( Array.isArray( this.data[ key ] ) ) {
        return this.data[ key ].map( function( prop ) {
          return prop.clone()
        })
      } else {
        return this.data[ key ].clone()
      }
  
    }
docs: Get a vCard property
  @param  {String} key
  @return {Object|Array}