Modify Power Query Custom Function to select Column

[brawnystaff]

I am using the Custom Function below to look for duplicate data in a table by two columns. When invoked, it gives me a drop down to search for Table, but I have to manually input the column names. Any ideas as to modify code to have the column names be drop-down list as well? Tried various declarations with no luck. Thanks.

let Dup = (DataTable as table, CCN as text, ClaimLine as text) =>

let
    Source = DataTable,
    #"Changed Type" = Table.TransformColumnTypes(Source,{{CCN, Int64.Type}, {ClaimLine, type text}}),
    #"Added Index" = Table.AddIndexColumn(#"Changed Type", "Index", 1, 1),
    #"Grouped Rows" = Table.Group(#"Added Index", {CCN}, {{"Data", each _, type table [CCN=nullable number, ClaimLine=nullable text, Index=number]}}),
    #"Added Custom" = Table.AddColumn(#"Grouped Rows", "Custom", each Table.AddIndexColumn([Data],"Instance",1)),
    #"Removed Other Columns" = Table.SelectColumns(#"Added Custom",{"Custom"}),
    #"Expanded Custom" = Table.ExpandTableColumn(#"Removed Other Columns", "Custom", {CCN, ClaimLine, "Index", "Instance"}, {CCN, ClaimLine, "Index", "Instance"}),
    #"Added Conditional Column" = Table.AddColumn(#"Expanded Custom", "Occurrence", each if [Instance] = 1 then "Original" else "Duplicate"),
    #"Sorted Rows" = Table.Sort(#"Added Conditional Column",{{"Index", Order.Ascending}}),
    #"Removed Columns" = Table.RemoveColumns(#"Sorted Rows",{"Index", "Instance"}),
    #"Changed Type1" = Table.TransformColumnTypes(#"Removed Columns",{{CCN, Int64.Type}, {ClaimLine, type text}, {"Occurrence", type text}})
in
    #"Changed Type1"
    in
    Dup