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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def create_results_dir(self):
 """Ensure that the empty results directory and a stable symlink exist for these versioned targets."""

    self._current_results_dir = self._cache_manager._results_dir_path(self.cache_key, stable=False)
    self._results_dir = self._cache_manager._results_dir_path(self.cache_key, stable=True)

    if not self.valid:
      # Clean the workspace for invalid vts.
      safe_mkdir(self._current_results_dir, clean=True)

    relative_symlink(self._current_results_dir, self._results_dir)
    self.ensure_legal()