def Command_Open():     # These are "stub" functions:
    return              # Functions that currently don't
                        # do anything, but eventually they
def Command_Save():     # will.  There is one function
    return              # for each "command" in the
                        # command processor.
def Command_Print():    # If the stub functions were not
    return              # present, the program would crash
                        # trying to call a function that
def Command_New():      # did not exist.  Once we figure
    return              # out what to do, we will fill in
                        # all the stubs with the correct code.

def Main():
    MoreToDo = True
    while MoreToDo:
        Command = input("Enter a command --- ")
        if   Command == "QUIT":  MoreToDo = False
        elif Command == "OPEN":  Command_Open()      # Call stub
        elif Command == "SAVE":  Command_Save()      # Call stub
        elif Command == "PRINT": Command_Print()     # Call stub
        elif Command == "NEW":   Command_New()       # Call stub
        else:                    print ("Illegal Command")

    return