code: def extract_from_text(text):
      
      # Remove the leading "arxiv:".
      return tools.remove_duplicates([re.sub("arxiv:", "", i[0],
                                             flags=re.IGNORECASE)
                                      for i in REGEX.findall(text) if i[0] != ''])
docs: Extract arXiv IDs from a text.
  
      :param text: The text to extract arXiv IDs from.
      :returns: A list of matching arXiv IDs, in canonical form.
  
      >>> sorted(extract_from_text('1506.06690 1506.06690v1 arXiv:1506.06690 arXiv:1506.06690v1 arxiv:1506.06690 arxiv:1506.06690v1 math.GT/0309136 abcdf bar1506.06690foo mare.GG/0309136'))
      ['1506.06690', '1506.06690v1', 'math.GT/0309136']