class_docstr: Abstract implementation of OAuth 1.0 and 1.0a.
  
  See `TwitterMixin` below for an example implementation.
  
  Class attributes:
  
  * ``_OAUTH_AUTHORIZE_URL``: The service's OAuth authorization url.
  * ``_OAUTH_ACCESS_TOKEN_URL``: The service's OAuth access token url.
  * ``_OAUTH_VERSION``: May be either "1.0" or "1.0a".
  * ``_OAUTH_NO_CALLBACKS``: Set this to True if the service requires
    advance registration of callbacks.
  
  Subclasses must also override the `_oauth_get_user_future` and
  `_oauth_consumer_token` methods.
class_docstr_tok: ["Abstract","implementation","of","OAuth","1.0","and","1.0a",".","See","`","TwitterMixin","`","below","for","an","example","implementation",".","Class","attributes",":","*","``","_OAUTH_AUTHORIZE_URL","``",":","The","service","'s","OAuth","authorization","url",".","*","``","_OAUTH_ACCESS_TOKEN_URL","``",":","The","service","'s","OAuth","access","token","url",".","*","``","_OAUTH_VERSION","``",":","May","be","either","``","1.0","''","or","``","1.0a","''",".","*","``","_OAUTH_NO_CALLBACKS","``",":","Set","this","to","True","if","the","service","requires","advance","registration","of","callbacks",".","Subclasses","must","also","override","the","`","_oauth_get_user_future","`","and","`","_oauth_consumer_token","`","methods","."]
code: def _oauth_get_user(self, access_token, callback):
      raise NotImplementedError()
  
imports: from __future__ import absolute_import, division, print_function
  import base64
  import binascii
  import functools
  import hashlib
  import hmac
  import time
  import uuid
  from tornado.concurrent import TracebackFuture, return_future, chain_future
  from tornado import gen
  from tornado import httpclient
  from tornado import escape
  from tornado.httputil import url_concat
  from tornado.log import gen_log
  from tornado.stack_context import ExceptionStackContext
  from tornado.util import unicode_type, ArgReplacer, PY3
label_desc: Use image node_id 9 for calling the OAuthMixin obj's underlying member method code with example usage: obj._oauth_get_user(access_token, callback) without return types