docs: def setDocumentedBy(self, documented_pid, documenting_pid):
          """Add a CiTO, the Citation Typing Ontology, triple asserting that
          ``documented_pid`` isDocumentedBy ``documenting_pid``.
  
          Adds assertion: ``documented_pid cito:isDocumentedBy documenting_pid``
  
          Args:
            documented_pid: str
              PID of a Science Object that is documented by ``documenting_pid``.
  
            documenting_pid: str
              PID of a Science Object that documents ``documented_pid``.
  
          """
          self._check_initialized()
          documented_id = self.getObjectByPid(documented_pid)
          documenting_id = self.getObjectByPid(documenting_pid)
          self.add((documented_id, CITO.isDocumentedBy, documenting_id))