code: def local_datafile(self):
          
          from ambry_sources import MPRowsFile
          from fs.errors import ResourceNotFoundError
          from ambry.orm.exc import NotFoundError
  
          try:
              return MPRowsFile(self._bundle.build_fs, self.cache_key)
  
          except ResourceNotFoundError:
              raise NotFoundError(
                  'Could not locate data file for partition {} (local)'.format(self.identity.fqname))
docs: Return the datafile for this partition, from the build directory, the remote, or the warehouse