code: def generate(mnx_dump):
      
      LOGGER.info("Read shortlist.")
      targets = pd.read_table(join(dirname(__file__), "shortlist.tsv"))
      if not exists(mnx_dump):
          # Download the MetaNetX chemicals dump if it doesn't exists.
          # Download done as per https://stackoverflow.com/a/16696317.
          LOGGER.info("MetaNetX dump '%s' does not exist. Downloading...",
                      mnx_dump)
          with open(mnx_dump, "wb") as file_handle, \
              get("https://www.metanetx.org/cgi-bin/mnxget/mnxref/chem_xref.tsv",
                  stream=True) as stream:
              for chunk in stream.iter_content(chunk_size=1024):
                  file_handle.write(chunk)
          LOGGER.info("Done.")
      LOGGER.info("Read the MetaNetX dump with cross-references.")
      db = pd.read_table(mnx_dump, comment='#',
                         names=['XREF', 'MNX_ID', 'Evidence', 'Description'])
      LOGGER.info("Generate the shortlist cross-references.")
      res = generate_shortlist(db, targets)
      LOGGER.info("Save result.")
      res.to_json(join(dirname(__file__), pardir, "memote", "support", "data",
                       "met_id_shortlist.json"), force_ascii=False)
docs: Annotate a shortlist of metabolites with cross-references using MetaNetX.
  
      MNX_DUMP : The chemicals dump from MetaNetX usually called 'chem_xref.tsv'.
          Will be downloaded if it doesn't exist.