def ensure_clean(self):
if not self.is_clean:<EOL><INDENT>raise WorkingTreeNotCleanError(compact("""<STR_LIT>""", local=format_path(self.local)))<EOL><DEDENT>
Make sure the working tree is clean (contains no changes to tracked files).

:raises: :exc:`~vcs_repo_mgr.exceptions.WorkingTreeNotCleanError`
         when the working tree contains changes to tracked files.