code: def get_extr_license_ident(self, extr_lic):
          
          identifier_tripples = list(self.graph.triples((extr_lic, self.spdx_namespace['licenseId'], None)))
  
          if not identifier_tripples:
              self.error = True
              msg = 'Extracted license must have licenseId property.'
              self.logger.log(msg)
              return
  
          if len(identifier_tripples) > 1:
              self.more_than_one_error('extracted license identifier_tripples')
              return
  
          identifier_tripple = identifier_tripples[0]
          _s, _p, identifier = identifier_tripple
          return identifier
docs: Return an a license identifier from an ExtractedLicense or None.