code: def add(self, fragment, sort=True):
          
          self._check_boundaries(fragment)
          if sort:
              if not self.is_guaranteed_sorted:
                  self.log_exc(u"Unable to add with sort=True if the list is not guaranteed sorted", None, True, ValueError)
              self._check_overlap(fragment)
              insort(self.__fragments, fragment)
              # self.log(u"Inserted and kept sorted flag true")
          else:
              self.__fragments.append(fragment)
              self.__sorted = False
docs: Add the given fragment to the list (and keep the latter sorted).
  
          An error is raised if the fragment cannot be added,
          for example if its interval violates the list constraints.
  
          :param fragment: the fragment to be added
          :type  fragment: :class:`~aeneas.syncmap.SyncMapFragment`
          :param bool sort: if ``True`` ensure that after the insertion the list is kept sorted
          :raises TypeError: if ``interval`` is not an instance of ``TimeInterval``
          :raises ValueError: if ``interval`` does not respect the boundaries of the list
                              or if it overlaps an existing interval,
                              or if ``sort=True`` but the list is not guaranteed sorted