Converts A List To A Printable String?

I have the following code:

Public Shared Function GetListAsString(ByVal data As List(Of String)) As String
Dim retVal As String = "| "
For Each obj As String In data[cod

It converts a List to a printable String. Right now it is set up to work with just Lists. I feel as if it should be able to work with any type of Collection. I am new to Collections and generics.When I attempt to do something like

Public Shared Function GetListAsString(ByVal data As Collection(T)) As String
Dim retVal As String = "| "
For Each obj As String In data.ToString()[code].....