code: def has_all_changes_covered(self):
          
          for filename in self.files():
              for hunk in self.file_source_hunks(filename):
                  for line in hunk:
                      if line.reason is None:
                          continue  # line untouched
                      if line.status is False:
                          return False  # line not covered
          return True
docs: Return `True` if all changes have been covered, `False` otherwise.