code: def children_not_empty(self):
          
          children = []
          for child_node in self.fragments_tree.children_not_empty:
              child_text_file = self.get_subtree(child_node)
              child_text_file.set_language(child_node.value.language)
              children.append(child_text_file)
          return children
docs: Return the direct not empty children of the root of the fragments tree,
          as ``TextFile`` objects.
  
          :rtype: list of :class:`~aeneas.textfile.TextFile`