code: def pif_search(self, pif_system_returning_query):
          
  
          self._validate_search_query(pif_system_returning_query)
          return self._execute_search_query(
              pif_system_returning_query,
              PifSearchResult
          )
docs: Run a PIF query against Citrination.
  
          :param pif_system_returning_query: The PIF system query to execute.
          :type pif_system_returning_query: :class:`PifSystemReturningQuery`
          :return: :class:`PifSearchResult` object with the results of the query.
          :rtype: :class:`PifSearchResult`