Convert coordinates lambert 93 {[Coordinate X],[Coordinate Y]} into Latitude and Longitude

Hi ams1 ,

Thanks for your advice, I tried so, but the code does not seem to work, I ended up with the following code

let
    Source = #"RPLS", // replace <Table> with the name of your source table
    #"Added Custom" = Table.AddColumn(Source, "Lat_Long", each let
        x = [Coordonnée X], // replace [Coordonnée X] with the name of your Lambert X coordinate column
        y = [Coordonnée Y], // replace [Coordonnée Y] with the name of your Lambert Y coordinate column
        wgs84 = List.Transform(
                  CoordinateSystem.Transform( #"EPSG:2154", #"EPSG:4326", {x, y} ), 
                  each Number.Round(_, 7)
                ),
        lat = wgs84{0},
        long = wgs84{1}
    ),
    #"Expanded Lat_Long" = Table.ExpandListColumn(#"Added Custom", "Lat_Long"),
    #"Renamed Columns" = Table.RenameColumns(#"Expanded Lat_Long", {"Lat_Long", "Lat_Long_WGS"}),
    #"Expanded Lat_Long_WGS" = Table.ExpandListColumn(#"Renamed Columns", "Lat_Long_WGS"),
    #"Extracted Values" = Table.TransformColumns(#"Expanded Lat_Long_WGS", {{"Lat_Long_WGS", each Text.Combine(List.Transform(_, Text.From), ","), type text}}),
    #"Split Column by Delimiter" = Table.SplitColumn(#"Extracted Values", "Lat_Long_WGS", Splitter.SplitTextByDelimiter(",", QuoteStyle.Csv), {"Latitude", "Longitude"}),
    #"Changed Type" = Table.TransformColumnTypes(#"Split Column by Delimiter",{{"Latitude", type number}, {"Longitude", type number}})
in
    #"Changed Type"

 It looked like after prompting CHatgpt that 

CoordinateSystem.Transform

 function is the source of the problem as it looks like I have to load a library, but I am not quite sure to do so when I looked into the one it adviced me to load but I guess I have to download from somewhere, but where to download it and where to load it?

Spatial = Extension.Load("Microsoft.Mashup.Engine1.Library.Spatial")

Also, why the code does not take into account the variable "Spatial"?

Many thanks for your help

Have a nice day