def isProperStage(stage):
    """Checks if the stage is a proper stage

        Arguments:
          stage(list) a 3x3 list containg a tic-tac-toe stage

        Returns:
          retVal(bool) True if the stage is a 3x3 list
    """
    retVal = True
    if type(stage) == list and len(stage) == 3:
        for row in stage:
            if not (type(row) == list and len(row) == 3):
                retVal = False
                break #No need to continue if even 1 row is bad
    elif not (type(stage) == list and len(stage) == 9):
        retVal = False

    return retVal