Type Alias OrderValidityType

OrderValidityType:
    | "AUTO"
    | "GFD"
    | "GTC"
    | "GTU"
    | "GTD"
    | "EOM"
    | "GTDT"
    | "IOC"

Order validity:

AUTO: choose automatically
GFD: good for day (today/current trading day)
GTC: good til canceled
GTD good til given date
GTU good til ultimo (end of month)
GTDT good til given date time
IOC immediate or cancel