original_docstring: 
      return nodes which you can't traverse down any further
      
docstring: return nodes which you can't traverse down any further
docstring_tokens: return nodes which you can ' t traverse down any further
code: def find_roots(graph):
      """
      return nodes which you can't traverse down any further
      """
      return [n for n in graph.nodes() if len(list(graph.predecessors(n))) == 0]
code_tokens: def find_roots ( graph ) : return [ n for n in graph . nodes ( ) if len ( list ( graph . predecessors ( n ) ) ) == 0 ]
short_docstring: return nodes which you can't traverse down any further
short_docstring_tokens: return nodes which you can ' t traverse down any further
comment: """
      return nodes which you can't traverse down any further
      """