docs: def illegal_doi(self, doi_string):
          """
          DOI string did not match the regex. Determine what the data is.
          :param doi_string: (str) Malformed DOI string
          :return: None
          """
          logger_doi_resolver.info("enter illegal_doi")
          # Ignores empty or irrelevant strings (blank, spaces, na, nan, ', others)
          if len(doi_string) > 5:
  
              # NOAA string
              if 'noaa' in doi_string.lower():
                  self.noaa_citation(doi_string)
  
              # Paragraph citation / Manual citation
              elif doi_string.count(' ') > 3:
                  self.root_dict['pub'][0]['citation'] = doi_string
  
              # Strange Links or Other, send to quarantine
              else:
                  logger_doi_resolver.warn("illegal_doi: bad doi string: {}".format(doi_string))
          logger_doi_resolver.info("exit illegal_doi")
          return