<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def __disclaimer(opt=""):
 """ Print the disclaimers once. If they've already been shown, skip over. :return none: """

    global settings
    if opt is "update":
        print("Disclaimer: LiPD files may be updated and modified to adhere to standards\n")
        settings["note_update"] = False
    if opt is "validate":
        print("Note: Use lipd.validate() or www.LiPD.net/create "
              "to ensure that your new LiPD file(s) are valid")
        settings["note_validate"] = False
    return