def _generate_update_diffs(self, pull_request, pull_request_version):
diff_context = (self.DIFF_CONTEXT +
ChangesetCommentsModel.needed_extra_diff_context())
old_diff = self._get_diff_from_pr_or_version(pull_request_version,
context=diff_context)
new_diff = self._get_diff_from_pr_or_version(pull_request,
context=diff_context)
old_diff_data = diffs.DiffProcessor(old_diff)
old_diff_data.prepare()
new_diff_data = diffs.DiffProcessor(new_diff)
new_diff_data.prepare()
return old_diff_data, new_diff_data
