The distribution of DataONE Common Library for Python is best installed using easy_install.
$ sudo easy_install DataONE_LibClient
The source code is available for the Client library, as well as the Common library, from the DataONE subversion repository:
$ svn co https://repository.dataone.org/software/cicore/tags/D1_COMMON_PYTHON_v1.0.1 d1_common_python
$ svn co https://repository.dataone.org/software/cicore/tags/D1_LIBCLIENT_PYTHON_v1.0.1 d1_libclient_python
Then change into, and install, each package:
$ cd d1_common_python
$ python setup.py install --user
$ cd ../d1_libclient_python
$ python setup.py install --user
$ cd ..