def _ReadTableHeader(self, file_object, table_header_offset):
    """Reads the table header.

    Args:
      file_object (file): file-like object.
      table_header_offset (int): offset of the tables header relative to
          the start of the file.

    Returns:
      keychain_table_header: table header.

    Raises:
      ParseError: if the table header cannot be read.
    """
    data_type_map = self._GetDataTypeMap('keychain_table_header')

    table_header, _ = self._ReadStructureFromFileObject(
        file_object, table_header_offset, data_type_map)

    return table_header
Reads the table header.

    Args:
      file_object (file): file-like object.
      table_header_offset (int): offset of the tables header relative to
          the start of the file.

    Returns:
      keychain_table_header: table header.

    Raises:
      ParseError: if the table header cannot be read.