def _build_chunk_headers(self):
if hasattr(self, "<STR_LIT>") and self._chunk_headers:<EOL><INDENT>return<EOL><DEDENT>self._chunk_headers = {}<EOL>for field in self._files:<EOL><INDENT>self._chunk_headers[field] = self._headers(field, True)<EOL><DEDENT>for field in self._data:<EOL><INDENT>self._chunk_headers[field] = self._headers(field)<EOL><DEDENT>
Build headers for each field.