def traverse_topologically(start_node, get_parents, get_children, filter_func=None, yield_descendants_of_unyielded=False):
 return _traverse_generic(start_node, get_parents=get_parents, get_children=get_children, filter_func=filter_func, yield_descendants_of_unyielded=yield_descendants_of_unyielded)

def traverse_topologically ( start_node , get_parents , get_children , filter_func = None , yield_descendants_of_unyielded = False ) : return _traverse_generic ( start_node , get_parents = get_parents , get_children = get_children , filter_func = filter_func , yield_descendants_of_unyielded = yield_descendants_of_unyielded )
generator for yielding nodes of a tree in a topological sort .