pip错误：TypeError: parse() got an unexpected keyword argument 'transport_encoding'

Win10，ANACONDA3(64-bit)，Python3.6.2。ANACONDA Prompt中不能用pip命令安装包，并且是在安装了TensorFlow后才发生的。报错如下：

Exception:  
Traceback (most recent call last):  
  File "C:\ProgramData\Anaconda3\lib\site-packages\pip\basecommand.py", line 215, in main  
    status = self.run(options, args)  
  File "C:\ProgramData\Anaconda3\lib\site-packages\pip\commands\install.py", line 335, in run  
    wb.build(autobuilding=True)  
  File "C:\ProgramData\Anaconda3\lib\site-packages\pip\wheel.py", line 749, in build  
    self.requirement_set.prepare_files(self.finder)  
  File "C:\ProgramData\Anaconda3\lib\site-packages\pip\req\req_set.py", line 380, in prepare_files  
    ignore_dependencies=self.ignore_dependencies))  
  File "C:\ProgramData\Anaconda3\lib\site-packages\pip\req\req_set.py", line 554, in _prepare_file  
    require_hashes  
  File "C:\ProgramData\Anaconda3\lib\site-packages\pip\req\req_install.py", line 278, in populate_link  
    self.link = finder.find_requirement(self, upgrade)  
  File "C:\ProgramData\Anaconda3\lib\site-packages\pip\index.py", line 465, in find_requirement  
    all_candidates = self.find_all_candidates(req.name)  
  File "C:\ProgramData\Anaconda3\lib\site-packages\pip\index.py", line 423, in find_all_candidates  
    for page in self._get_pages(url_locations, project_name):  
  File "C:\ProgramData\Anaconda3\lib\site-packages\pip\index.py", line 568, in _get_pages  
    page = self._get_page(location)  
  File "C:\ProgramData\Anaconda3\lib\site-packages\pip\index.py", line 683, in _get_page  
    return HTMLPage.get_page(link, session=self.session)  
  File "C:\ProgramData\Anaconda3\lib\site-packages\pip\index.py", line 811, in get_page  
    inst = cls(resp.content, resp.url, resp.headers)  
  File "C:\ProgramData\Anaconda3\lib\site-packages\pip\index.py", line 731, in __init__  
    namespaceHTMLElements=False,  
TypeError: parse() got an unexpected keyword argument 'transport_encoding'   

解决办法：输入如下命令

conda install -c anaconda html5lib  

会看到一系列更新的结果，然后再次使用pip安装包，发现可以成功安装。

原文链接：https://blog.csdn.net/cheese_pop/article/details/78201359

另外：
在安装scrapy时，若总是提示失败，来需要安装Twisted，详情下https://www.cnblogs.com/liuliliuli2017/p/6746440.html