/// Escape `s` to be FinTS compliant.
fnescape_fints(s:&str)-> String{
s.replace("?","??").replace("+","?+").replace(":","?:").replace("@","?@")}/// Unescape `s` from a FinTS-escaped format.
fnunescape_fints(s:&str)-> String{
s.replace("??","?").replace("?+","+").replace("?:",":").replace("?@","@")}