code: def _WriteStorageMetadata(self):
      
      self._cursor.execute(self._CREATE_METADATA_TABLE_QUERY)
  
      query = 'INSERT INTO metadata (key, value) VALUES (?, ?)'
  
      key = 'format_version'
      value = '{0:d}'.format(self._FORMAT_VERSION)
      self._cursor.execute(query, (key, value))
  
      key = 'compression_format'
      value = self.compression_format
      self._cursor.execute(query, (key, value))
  
      key = 'serialization_format'
      value = self.serialization_format
      self._cursor.execute(query, (key, value))
  
      key = 'storage_type'
      value = self.storage_type
      self._cursor.execute(query, (key, value))
docs: Writes the storage metadata.