code: def read_local_manifest(self):
          
  
          manifest = file_or_default(self.get_full_file_path(self.manifest_file), {
              'format_version' : 2,
              'root'           : '/',
              'have_revision'  : 'root',
              'files'          : {}}, json.loads)
  
          if 'format_version' not in manifest or manifest['format_version'] < 2:
              raise SystemExit('Please update the client manifest format')
          return manifest
docs: Read the file manifest, or create a new one if there isn't one already