nodes: 0, module; 1, function_definition; 2, function_name:topological_sort; 3, parameters; 4, block; 5, identifier:self; 6, expression_statement; 7, expression_statement; 8, expression_statement; 9, for_statement; 10, for_statement; 11, expression_statement; 12, for_statement; 13, expression_statement; 14, while_statement; 15, if_statement; 16, comment:""" Returns a topological ordering of the DAG.
  
          Returns:
              list: A list of topologically sorted nodes in the graph.
  
          Raises:
              ValueError: Raised if the graph is not acyclic.
          """; 17, assignment; 18, assignment; 19, identifier:u; 20, identifier:graph; 21, block; 22, identifier:u; 23, identifier:graph; 24, block; 25, assignment; 26, identifier:u; 27, identifier:in_degree; 28, block; 29, assignment; 30, identifier:queue; 31, block; 32, comparison_operator:len(sorted_graph) == len(graph); 33, block; 34, else_clause; 35, identifier:graph; 36, attribute; 37, identifier:in_degree; 38, dictionary; 39, expression_statement; 40, for_statement; 41, identifier:queue; 42, call; 43, if_statement; 44, identifier:sorted_graph; 45, list; 46, expression_statement; 47, expression_statement; 48, for_statement; 49, call; 50, call; 51, return_statement; 52, block; 53, identifier:self; 54, identifier:graph; 55, assignment; 56, identifier:v; 57, subscript; 58, block; 59, identifier:deque; 60, argument_list; 61, comparison_operator:in_degree[u] == 0; 62, block; 63, assignment; 64, call; 65, identifier:v; 66, call; 67, block; 68, identifier:len; 69, argument_list; 70, identifier:len; 71, argument_list; 72, identifier:sorted_graph; 73, raise_statement; 74, subscript; 75, integer:0; 76, identifier:graph; 77, identifier:u; 78, expression_statement; 79, subscript; 80, integer:0; 81, expression_statement; 82, identifier:u; 83, call; 84, attribute; 85, argument_list; 86, identifier:sorted; 87, argument_list; 88, expression_statement; 89, if_statement; 90, identifier:sorted_graph; 91, identifier:graph; 92, call; 93, identifier:in_degree; 94, identifier:u; 95, augmented_assignment; 96, identifier:in_degree; 97, identifier:u; 98, call; 99, attribute; 100, argument_list; 101, identifier:sorted_graph; 102, identifier:append; 103, identifier:u; 104, subscript; 105, augmented_assignment; 106, comparison_operator:in_degree[v] == 0; 107, block; 108, identifier:ValueError; 109, argument_list; 110, subscript; 111, integer:1; 112, attribute; 113, argument_list; 114, identifier:queue; 115, identifier:pop; 116, identifier:graph; 117, identifier:u; 118, subscript; 119, integer:1; 120, subscript; 121, integer:0; 122, expression_statement; 123, string; 124, identifier:in_degree; 125, identifier:v; 126, identifier:queue; 127, identifier:appendleft; 128, identifier:u; 129, identifier:in_degree; 130, identifier:v; 131, identifier:in_degree; 132, identifier:v; 133, call; 134, string_content:graph is not acyclic; 135, attribute; 136, argument_list; 137, identifier:queue; 138, identifier:appendleft; 139, identifier:v
code: def topological_sort(self):
          """ Returns a topological ordering of the DAG.
  
          Returns:
              list: A list of topologically sorted nodes in the graph.
  
          Raises:
              ValueError: Raised if the graph is not acyclic.
          """
          graph = self.graph
  
          in_degree = {}
          for u in graph:
              in_degree[u] = 0
  
          for u in graph:
              for v in graph[u]:
                  in_degree[v] += 1
  
          queue = deque()
          for u in in_degree:
              if in_degree[u] == 0:
                  queue.appendleft(u)
  
          sorted_graph = []
          while queue:
              u = queue.pop()
              sorted_graph.append(u)
              for v in sorted(graph[u]):
                  in_degree[v] -= 1
                  if in_degree[v] == 0:
                      queue.appendleft(v)
  
          if len(sorted_graph) == len(graph):
              return sorted_graph
          else:
              raise ValueError('graph is not acyclic')