code: def add_string_pairs_from_label_element(xib_file, results, label, special_ui_components_prefix):
      
      label_entry_comment = extract_element_internationalized_comment(label)
      if label_entry_comment is None:
          return
  
      warn_if_element_not_of_class(label, 'Label', special_ui_components_prefix)
  
      if label.hasAttribute('usesAttributedText') and label.attributes['usesAttributedText'].value == 'YES':
          add_string_pairs_from_attributed_ui_element(results, label, label_entry_comment)
      else:
          try:
              label_entry_key = label.attributes['text'].value
          except KeyError:
              try:
                  label_entry_key = label.getElementsByTagName('string')[0].firstChild.nodeValue
              except Exception:
                  label_entry_key = 'N/A'
                  logging.warn("%s: Missing text entry in %s", xib_file, label.toxml('UTF8'))
          results.append((label_entry_key, label_entry_comment))
docs: Adds string pairs from a label element.
  
      Args:
          xib_file (str): Path to the xib file.
          results (list): The list to add the results to.
          label (element): The label element from the xib, to extract the string pairs from.
          special_ui_components_prefix (str):
              If not None, extraction will not warn about internationalized UI components with this class prefix.