InArgument IEnumerable

Question

How to transfer IEnumerable value into InArgument in CodeActivity in Workflow

public sealed class CreateInterview : CodeActivity<int>
    {        
public InArgument<List<InterviewerList>> InterviewerLists { get; set; }

protected override int Execute(CodeActivityContext context)
        {
var interviewerLists = context.GetValue(this.InterviewerLists); // interviewerLists = null
}

Hot to set and get IEnumerable Value