code: def _ParseDLSPageHeader(self, file_object, page_offset):
      
      page_header_map = self._GetDataTypeMap('dls_page_header')
  
      try:
        page_header, page_size = self._ReadStructureFromFileObject(
            file_object, page_offset, page_header_map)
      except (ValueError, errors.ParseError) as exception:
        raise errors.ParseError(
            'Unable to parse page header at offset: 0x{0:08x} '
            'with error: {1!s}'.format(page_offset, exception))
  
      if page_header.signature not in self._DLS_SIGNATURES:
        raise errors.UnableToParseFile(
            'Unsupported page header signature at offset: 0x{0:08x}'.format(
                page_offset))
  
      return page_header, page_size
docs: Parses a DLS page header from a file-like object.
  
      Args:
        file_object (file): file-like object to read the header from.
        page_offset (int): offset of the start of the page header, relative
            to the start of the file.
  
      Returns:
        tuple: containing:
  
          dls_page_header: parsed record structure.
          int: header size.
  
      Raises:
        ParseError: when the header cannot be parsed.