docs: def getObjectByPid(self, pid):
          """
      Args:
        pid : str
  
      Returns:
        str : URIRef of the entry identified by ``pid``."""
          self._check_initialized()
          opid = rdflib.term.Literal(pid)
          res = [o for o in self.subjects(predicate=DCTERMS.identifier, object=opid)]
          return res[0]