包 inputenc 错误：使用 {lstlisting} 的 UTF-8 字节序列无效

Question

我有下一个代码错误

codealcance.tex
58
Package inputenc Error: Invalid UTF-8 byte sequence.

See the inputenc package documentation for explanation.
Type  H <return>  for immediate help.
 ...                                              

l.58     while stack: #en cada iteración

这些是 57-59 行

   57print("\nantes\n")
    58while stack: #en cada iteración va agregando elementos que faltan por visitar a la pila
        59vertex = stack.pop()

这是 codealcance.tex

\begin{lstlisting}[caption={Segundo alcance DFS y orden topologico},label={lst:alcance2},style=customc]

import time
from collections import deque

class abstract_graph:

    def __init__(self,_edges):
        self.edges=_edges
        self.nodes={u for u,v in self.edges} | {v for u,v in self.edges}

    def adjacency_list(self):
        pass


class simple_digraph(abstract_graph):

    def __init__(self,_edges):
        self.edges=_edges
        print("las aristas: ", self.edges)
        self.nodes={u for u,v in self.edges if u!=None} | {v for u,v in self.edges if v!=None}
        a={u for u,v in self.edges if u!=None} #en una ariista (u,v) en a se guarda listsa con cada u
        b={v for u,v in self.edges if v!=None}
        c= a | b #en c se guarda la union de los nodos 


    def adjacency_list(self):
        adjacent=lambda n : {v for u,v in self.edges if u==n and v!=None} 
        return {v:adjacent(v) for v in self.nodes} #se crea un diccionario en el que la key es un nodo y los elementos del diccionario son nodos adyacentes

    def in_degree(self):
        degree= lambda n : len({u for u,v in self.edges if v==n and u!=None})
        return {v:degree(v) for v in self.nodes}


def topo_sort(graph):
    topology = []

    degree = graph.in_degree()
    adj=graph.adjacency_list()
    stack=[key for (key,value) in G.in_degree().items() if value==0] 
    while stack:
        vertex = stack.pop()
        topology.append(vertex)
        for m in adj[vertex]:
            degree[m] -= 1
            if not degree[m]:
                stack.append(m)

    if len(topology) < len(graph.nodes):
        raise ValueError('graph contains cycle')
    return topology


def dfs(graph, start):
    visited, stack, path = set(), [start],[]
    print("\nantes\n")
    while stack: #en cada iteración va agregando elementos que faltan por visitar a la pila
        vertex = stack.pop()
        print("\nel vertice:", vertex)
        if vertex not in visited:
            visited.add(vertex)

            path.append(vertex)

            stack.extend(graph[vertex] - visited)

    print("EL DFS es:",path)
    return path

E=[('LINK1', 'LINK2'),('LINK1', 'LINK4'),('LINK2', 'LINK3'),('LINK2', 'LINK5'),('LINK3', 'LINK4'),('LINK3', 'LINK5'),('LINK4', 'LINK5'),('LINK6', 'LINK7')]
G=simple_digraph(E)
print("LISTA ADYACENCIA", G.adjacency_list())
print("IN DEGREE",G.in_degree())

start=time.clock()
ddfs=dfs(G.adjacency_list(),'LINK1') #ejecuta la busqueda en proundidad

L=topo_sort(G) #ejecuta el ordenamiento topologico
print('\nOrden topologico',L)

\end{lstlisting}

在我的主程序中我添加了 utf8 包

\documentclass{article}
\usepackage[margin=1in]{geometry}
\usepackage[spanish,es-tabla]{babel} % espanol
\decimalpoint
\usepackage[utf8]{inputenc}              
\usepackage{graphicx} % graficos
\usepackage{amsmath}
\usepackage{listings}