Args:
        * offset - Integer - The positive / negative change to apply
          to the page.
        * max_page_count - The maximum number of pages available.
        * nom - None on Max or Min - If max number of pages reached,
          return none instead of forcing back into range.

    Returns:
        Boolean - True if successful, False if nom is True and the
        value was forced back within the boundry.

def change_subpage(self, offset=None, max_page_count=None, nom=True):
        """
    Args:
        * offset - Integer - The positive / negative change to apply
          to the page.
        * max_page_count - The maximum number of pages available.
        * nom - None on Max or Min - If max number of pages reached,
          return none instead of forcing back into range.

    Returns:
        Boolean - True if successful, False if nom is True and the
        value was forced back within the boundry.
        """
        if offset == None:
            return

        if self.slots['subpage'] == None:
            self.slots['subpage'] = 1

        if (self.slots['subpage']+offset > max_page_count) and nom:
            return None
        elif (self.slots['subpage']+offset < 1) and nom:
            return None
        else:
            self.slots['subpage'] = norm_page_cnt(\
                self.slots['subpage']+offset,
                max_page_count)
        return True