let
Source = Excel.CurrentWorkbook(){[Name="T_Data"]}[Content],
Début = Table.AddColumn(Source,"Date Début", each List.RemoveNulls(List.Transform(Text.Split([Colonne7],""""), each try Date.From(_) otherwise null)){0},type date),
Fin= Table.AddColumn(Début,"Date Fin", each List.RemoveNulls(List.Transform(Text.Split([Colonne7],""""), each try Date.From(_) otherwise null)){1},type date)
in
Fin