TypeError: a bytes-like object is required, not 'str'

[caot]

$ pip install mlab
Collecting mlab
  Using cached mlab-1.1.4.tar.gz
    Complete output from command python setup.py egg_info:
    running egg_info
    creating pip-egg-info/mlab.egg-info
    writing pip-egg-info/mlab.egg-info/PKG-INFO
    <string>:175: (WARNING/2) Literal block expected; none found.
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "/private/var/folders/q_/sz5vb9g57yg62_40hkg90jvw0000gq/T/pip-build-cgo45po5/mlab/setup.py", line 47, in <module>
        download_url='https://github.com/ewiger/mlab/tarball/master',
      File "/Applications/anaconda/lib/python3.6/distutils/core.py", line 148, in setup
        dist.run_commands()
      File "/Applications/anaconda/lib/python3.6/distutils/dist.py", line 955, in run_commands
        self.run_command(cmd)
      File "/Applications/anaconda/lib/python3.6/distutils/dist.py", line 974, in run_command
        cmd_obj.run()
      File "/Applications/anaconda/lib/python3.6/site-packages/setuptools-27.2.0-py3.6.egg/setuptools/command/egg_info.py", line 188, in run
      File "/Applications/anaconda/lib/python3.6/site-packages/setuptools-27.2.0-py3.6.egg/setuptools/command/egg_info.py", line 403, in write_pkg_info
      File "/Applications/anaconda/lib/python3.6/distutils/dist.py", line 1106, in write_pkg_info
        self.write_pkg_file(pkg_info)
      File "/Applications/anaconda/lib/python3.6/site-packages/setuptools-27.2.0-py3.6.egg/setuptools/dist.py", line 53, in write_pkg_file
      File "/Applications/anaconda/lib/python3.6/distutils/util.py", line 474, in rfc822_escape
        lines = header.split('\n')
    TypeError: a bytes-like object is required, not 'str'