code: def upsert(self, doc, namespace, timestamp):
          
          if self.auto_commit_interval is not None:
              self.solr.add([self._clean_doc(doc, namespace, timestamp)],
                            commit=(self.auto_commit_interval == 0),
                            commitWithin=u(self.auto_commit_interval))
          else:
              self.solr.add([self._clean_doc(doc, namespace, timestamp)],
                            commit=False)
docs: Update or insert a document into Solr
  
          This method should call whatever add/insert/update method exists for
          the backend engine and add the document in there. The input will
          always be one mongo document, represented as a Python dictionary.