serverless-python-requirements: pip install exception on sls deployment

Hi,

Thanks the plugin. I am currently having a problem with deploying my small service which is open source luckily. See: https://github.com/helveticafire/serverless-pynamodb-rest-example

Is there something I am missing? Or doing wrong?

It was previously working unfortunately I have not got far enough with CI for auto-deployment to prevent this from happening.

$ sls deploy

Result:

Serverless: Parsing Python requirements.txt
Serverless: Installing required Python packages for runtime python3.6...

  Error --------------------------------------------------

  Exception:
Traceback (most recent call last):
  File "/usr/local/lib/python3.6/site-packages/pip/basecommand.py", line 215, in main
    status = self.run(options, args)
  File "/usr/local/lib/python3.6/site-packages/pip/commands/install.py", line 342, in run
    prefix=options.prefix_path,
  File "/usr/local/lib/python3.6/site-packages/pip/req/req_set.py", line 784, in install
    **kwargs
  File "/usr/local/lib/python3.6/site-packages/pip/req/req_install.py", line 851, in install
    self.move_wheel_files(self.source_dir, root=root, prefix=prefix)
  File "/usr/local/lib/python3.6/site-packages/pip/req/req_install.py", line 1064, in move_wheel_files
    isolated=self.isolated,
  File "/usr/local/lib/python3.6/site-packages/pip/wheel.py", line 247, in move_wheel_files
    prefix=prefix,
  File "/usr/local/lib/python3.6/site-packages/pip/locations.py", line 153, in distutils_scheme
    i.finalize_options()
  File "/usr/local/Cellar/python3/3.6.2/Frameworks/Python.framework/Versions/3.6/lib/python3.6/distutils/command/install.py", line 248, in finalize_options
    "must supply either home or prefix/exec-prefix -- not both")
distutils.errors.DistutilsOptionError: must supply either home or prefix/exec-prefix -- not both


     For debugging logs, run again after setting the "SLS_DEBUG=*" environment variable.

  Stack Trace --------------------------------------------

Error: Exception:
Traceback (most recent call last):
  File "/usr/local/lib/python3.6/site-packages/pip/basecommand.py", line 215, in main
    status = self.run(options, args)
  File "/usr/local/lib/python3.6/site-packages/pip/commands/install.py", line 342, in run
    prefix=options.prefix_path,
  File "/usr/local/lib/python3.6/site-packages/pip/req/req_set.py", line 784, in install
    **kwargs
  File "/usr/local/lib/python3.6/site-packages/pip/req/req_install.py", line 851, in install
    self.move_wheel_files(self.source_dir, root=root, prefix=prefix)
  File "/usr/local/lib/python3.6/site-packages/pip/req/req_install.py", line 1064, in move_wheel_files
    isolated=self.isolated,
  File "/usr/local/lib/python3.6/site-packages/pip/wheel.py", line 247, in move_wheel_files
    prefix=prefix,
  File "/usr/local/lib/python3.6/site-packages/pip/locations.py", line 153, in distutils_scheme
    i.finalize_options()
  File "/usr/local/Cellar/python3/3.6.2/Frameworks/Python.framework/Versions/3.6/lib/python3.6/distutils/command/install.py", line 248, in finalize_options
    "must supply either home or prefix/exec-prefix -- not both")
distutils.errors.DistutilsOptionError: must supply either home or prefix/exec-prefix -- not both

    at module.exports.logError (/Users/benfitzgerald/.nvm/versions/node/v7.5.0/lib/node_modules/serverless/lib/classes/Error.js:94:11)
    at initializeErrorReporter.then.catch.e (/Users/benfitzgerald/.nvm/versions/node/v7.5.0/lib/node_modules/serverless/bin/serverless:42:3)
    at runCallback (timers.js:651:20)
    at tryOnImmediate (timers.js:624:5)
    at processImmediate [as _immediateCallback] (timers.js:596:5)
From previous event:
    at __dirname (/Users/benfitzgerald/.nvm/versions/node/v7.5.0/lib/node_modules/serverless/bin/serverless:40:9)
    at Object.<anonymous> (/Users/benfitzgerald/.nvm/versions/node/v7.5.0/lib/node_modules/serverless/bin/serverless:43:4)
    at Module._compile (module.js:571:32)
    at Object.Module._extensions..js (module.js:580:10)
    at Module.load (module.js:488:32)
    at tryModuleLoad (module.js:447:12)
    at Function.Module._load (module.js:439:3)
    at Module.runMain (module.js:605:10)
    at run (bootstrap_node.js:418:7)
    at startup (bootstrap_node.js:139:9)
    at bootstrap_node.js:533:3

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  Your Environment Information -----------------------------
     OS:                     darwin
     Node Version:           7.5.0
     Serverless Version:     1.19.0