Storing picklist attribute

Hallo,
how to store picklist attribute for term\concept with multiple values using GroupShare MultiTerm API?
The following code does not work unfortunately:

var picklistAttribute = new Attribute
{
     Name = "Part Of Speech",
     Value = new List<Types>
     {
         new Types
         {
            Value = "Verb",
            Type = "Picklist"
          },
          new Types
          {
             Value = "Noun",
             Type = "Picklist"
          }
     }
};