code: def modify_filename_id(filename):
      
      split_filename = os.path.splitext(filename)
      id_num_re = re.compile('(\(\d\))')
      id_num = re.findall(id_num_re, split_filename[-2])
      if id_num:
          new_id_num = int(id_num[-1].lstrip('(').rstrip(')')) + 1
  
          # Reconstruct filename with incremented id and its extension
          filename = ''.join((re.sub(id_num_re, '({0})'.format(new_id_num),
                                     split_filename[-2]), split_filename[-1]))
      else:
          split_filename = os.path.splitext(filename)
  
          # Reconstruct filename with new id and its extension
          filename = ''.join(('{0} (2)'.format(split_filename[-2]),
                              split_filename[-1]))
      return filename
docs: Modify filename to have a unique numerical identifier.