code: def add_fragment(self, fragment, as_last=True):
          
          if not isinstance(fragment, SyncMapFragment):
              self.log_exc(u"fragment is not an instance of SyncMapFragment", None, True, TypeError)
          self.fragments_tree.add_child(Tree(value=fragment), as_last=as_last)
docs: Add the given sync map fragment,
          as the first or last child of the root node
          of the sync map tree.
  
          :param fragment: the sync map fragment to be added
          :type  fragment: :class:`~aeneas.syncmap.fragment.SyncMapFragment`
          :param bool as_last: if ``True``, append fragment; otherwise prepend it
          :raises: TypeError: if ``fragment`` is ``None`` or
                              it is not an instance of :class:`~aeneas.syncmap.fragment.SyncMapFragment`