尽管已经安装了，我仍然会收到此错误。检查以下内容：
MacBook:examples User$ python
Python 2.7.6 (default, Sep 9 2014, 15:04:36)
[GCC 4.2.1 Compatible Apple LLVM 6.0 (clang-600.0.39)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from whatsapp import Client
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/Library/Python/2.7/site-packages/whatsapp.py", line 5, in <module>
from yowsup import env
ImportError: No module named yowsup
>>> quit()
MacBook:examples User$ sudo pip install yowsup
Password:
The directory '/Users/User/Library/Caches/pip/http' or its parent directory is not owned by the current user and the cache has been disabled. Please check the permissions and owner of that directory. If executing pip with sudo, you may want sudo's -H flag.
The directory '/Users/User/Library/Caches/pip' or its parent directory is not owned by the current user and caching wheels has been disabled. check the permissions and owner of that directory. If executing pip with sudo, you may want sudo's -H flag.
Requirement already satisfied (use --upgrade to upgrade): yowsup in /Library/Python/2.7/site-packages