mac 下执行pip报错TypeError

在终端输入任何pip 相关的任何命令都会报错：

File "/usr/local/bin/pip", line 11, in <module>
    load_entry_point('pip==10.0.1', 'console_scripts', 'pip')()
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/pkg_resources/__init__.py", line 489, in load_entry_point
    return get_distribution(dist).load_entry_point(group, name)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/pkg_resources/__init__.py", line 2843, in load_entry_point
    return ep.load()
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/pkg_resources/__init__.py", line 2434, in load
    return self.resolve()
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/pkg_resources/__init__.py", line 2440, in resolve
    module = __import__(self.module_name, fromlist=['__name__'], level=0)
  File "/Library/Python/2.7/site-packages/pip-10.0.1-py2.7.egg/pip/_internal/__init__.py", line 42, in <module>
    from pip._internal import cmdoptions
  File "/Library/Python/2.7/site-packages/pip-10.0.1-py2.7.egg/pip/_internal/cmdoptions.py", line 16, in <module>
    from pip._internal.index import (
  File "/Library/Python/2.7/site-packages/pip-10.0.1-py2.7.egg/pip/_internal/index.py", line 15, in <module>
    from pip._vendor import html5lib, requests, six
  File "/Library/Python/2.7/site-packages/pip-10.0.1-py2.7.egg/pip/_vendor/requests/__init__.py", line 86, in <module>
    from pip._vendor.urllib3.contrib import pyopenssl
  File "/Library/Python/2.7/site-packages/pip-10.0.1-py2.7.egg/pip/_vendor/urllib3/contrib/pyopenssl.py", line 46, in <module>
    import OpenSSL.SSL
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/OpenSSL/__init__.py", line 8, in <module>
    from OpenSSL import crypto, SSL
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/OpenSSL/crypto.py", line 12, in <module>
    from cryptography import x509
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/cryptography/x509/__init__.py", line 8, in <module>
    from cryptography.x509.base import (
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/cryptography/x509/base.py", line 16, in <module>
    from cryptography.x509.extensions import Extension, ExtensionType
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/cryptography/x509/extensions.py", line 24, in <module>
    from cryptography.x509.general_name import GeneralName, IPAddress, OtherName
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/cryptography/x509/general_name.py", line 16, in <module>
    from cryptography.x509.name import Name
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/cryptography/x509/name.py", line 28, in <module>
    _ASN1_TYPE_TO_ENUM = dict((i.value, i) for i in _ASN1Type)
TypeError: 'type' object is not iterable

资料方案

1. 方法1
   查找资料说可以如下解决：

sudo pip uninstall enum
sudo pip install enum34

但是该命令仍然会报上述错误。

2. 资料2
   手动移除

• Removed enum from "/usr/lib/python2.7/dist-packages": rm -rf enum*
• When I tried to install enum34 using "pip install enum34" I still run into the same error from cryptography: "TypeError: 'type' object is not iterable". (I think its because there is a copy of enum present under "/usr/local/lib/python2.7/dist-packages" as well.
• Next I removed cryptography from "/usr/lib/python2.7/dist-packages": rm -rf cryptography*
• Now try running "pip uninstall enum", it works.
• Then install enum34: pip install enum34
• Then install cryptography again: pip install cryptography

最终解决

• command + space按键打开搜索栏，输入/library打开资源库
• 进入/Library/Python/2.7目录中发现只有site-packages目录，且里面有enum相关的文件，应该是之前自己通过pip install enum命令添加的
• 输入sudo rm -rf enum*
• 安装enum，pip install enum34

参考

• https://stackoverflow.com/questions/49509790/typeerror-when-importing-requests-from-python
• https://github.com/pyca/cryptography/issues/4020