builder for '/nix/store/7cc9snhy0kjsskb77mb23fm2z8f03rr9-python2.7-betacode-1.0.drv' failed with exit code 1; last 10 log lines:
  Executing setuptoolsBuildPhase
  Traceback (most recent call last):
    File "nix_run_setup", line 8, in <module>
      exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\\r\\n', '\\n'), __file__, 'exec'))
    File "setup.py", line 22, in <module>
      long_description = read('README.rst'),
    File "setup.py", line 14, in read
      with open(os.path.join(os.path.dirname(__file__), fn), encoding='utf-8') as f:
  TypeError: 'encoding' is an invalid keyword argument for this function
  builder for '/nix/store/7cc9snhy0kjsskb77mb23fm2z8f03rr9-python2.7-betacode-1.0.drv' failed with exit code 1
cannot build derivation '/nix/store/shllrgfahfx5di0vpkigkq0s5znwncp5-env.drv': 1 dependencies couldn't be built