I believe it is just a mistake of the type Ctrl + C Ctrl + V, but the code today is as follows:

function TMVCRESTClient.AddQueryStringParam(const aName: string; aValue: Double): IMVCRESTClient;
begin
Result := AddPathParam(aName, aValue.ToString);
end;

When in fact I believe it must be something like:

function TMVCRESTClient.AddQueryStringParam(const aName: string; aValue: Double): IMVCRESTClient;
begin
Result := AddQueryStringParam(aName, aValue.ToString);
end;