code: def _check_min_max_indices(self, min_index=None, max_index=None):
          
          min_index = min_index or 0
          max_index = max_index or len(self)
          if min_index < 0:
              self.log_exc(u"min_index is negative", None, True, ValueError)
          if max_index > len(self):
              self.log_exc(u"max_index is bigger than the number of intervals in the list", None, True, ValueError)
          return min_index, max_index
docs: Ensure the given start/end fragment indices make sense:
          if one of them is ``None`` (i.e., not specified),
          then set it to ``0`` or ``len(self)``.