Replace urllib.urlopen to urllib.request.urlopen

[jhleee]

python3 raise AttributeError.

Traceback (most recent call last):
  File "/usr/local/lib/python3.5/dist-packages/flask/app.py", line 1836, in __call__
    return self.wsgi_app(environ, start_response)
  File "/usr/local/lib/python3.5/dist-packages/flask/app.py", line 1820, in wsgi_app
    response = self.make_response(self.handle_exception(e))
  File "/usr/local/lib/python3.5/dist-packages/flask_restful/__init__.py", line 270, in error_router
    return original_handler(e)
  File "/usr/local/lib/python3.5/dist-packages/flask/app.py", line 1403, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "/usr/local/lib/python3.5/dist-packages/flask/_compat.py", line 32, in reraise
    raise value.with_traceback(tb)
  File "/usr/local/lib/python3.5/dist-packages/flask/app.py", line 1817, in wsgi_app
    response = self.full_dispatch_request()
  File "/usr/local/lib/python3.5/dist-packages/flask/app.py", line 1477, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/usr/local/lib/python3.5/dist-packages/flask_restful/__init__.py", line 270, in error_router
    return original_handler(e)
  File "/usr/local/lib/python3.5/dist-packages/flask/app.py", line 1381, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/usr/local/lib/python3.5/dist-packages/flask/_compat.py", line 32, in reraise
    raise value.with_traceback(tb)
  File "/usr/local/lib/python3.5/dist-packages/flask/app.py", line 1475, in full_dispatch_request
    rv = self.dispatch_request()
  File "/usr/local/lib/python3.5/dist-packages/flask/app.py", line 1461, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/usr/local/lib/python3.5/dist-packages/flask_restful/__init__.py", line 462, in wrapper
    resp = resource(*args, **kwargs)
  File "/usr/local/lib/python3.5/dist-packages/flask/views.py", line 84, in view
    return self.dispatch_request(*args, **kwargs)
  File "/usr/local/lib/python3.5/dist-packages/flask_restful/__init__.py", line 572, in dispatch_request
    resp = meth(*args, **kwargs)
  File "/media/sf_workspace/python/flask/codebot_kakao/app.py", line 66, in post
    url = save_to_pastebin(code, format="python")
  File "/media/sf_workspace/python/flask/codebot_kakao/app.py", line 28, in save_to_pastebin
    paste_private = 'unlisted')
  File "/usr/local/lib/python3.5/dist-packages/pastebin.py", line 679, in paste
    request_string = urllib.urlopen(self._api_url, urllib.urlencode(argv))
AttributeError: module 'urllib' has no attribute 'urlopen'

It should be replace to urllib.request.urlopen

[csm10495]

There's a bit more too here, we'll also run into issues with urlencode(), etc. Using the six package would be a better way to go about this. @Morrolan are you open to pull requests to make this work on both py2 and py3?

[bitsnaps]

Got the same issue on colab, looks like pip package is outdated!