python3 UnicodeEncodeError: 'gbk' codec can't encode character 'xa0' in position 30: illegal multibyte sequence

　　昨天用用python3写个日志文件，结果报错UnicodeEncodeError: 'gbk' codec can't encode character 'xa0' in position 30: illegal multibyte sequence

　　具体代码是：

　　with open(fileName, 'a') as f：

　　　　f.write(message)

　　后来改成如下：

　　with open(fileName, 'a',encoding='utf-8') as f：

　　　　f.write(message)

　　就可以了。还是编码的问题