'Create access token.
For more information, please refer to the official API reference:
http://developer.openstack.org/api-ref/identity/v3-ext/#create-access-token'

def create_access_token(self, consumer_key, consumer_secret, request_key, request_secret, oauth_verifier):

    endpoint = 'OS-OAUTH1/access_token'
    oauth_params = self._generate_params_with_signature(consumer_key, ((self.base_url + '/') + endpoint), client_secret=consumer_secret, resource_owner_key=request_key, resource_owner_secret=request_secret, verifier=oauth_verifier, http_method='POST')
    headers = self._generate_oauth_header(oauth_params)
    (resp, body) = self.post(endpoint, body=None, headers=headers)
    self.expected_success(201, resp.status)
    if (not isinstance(body, str)):
        body = body.decode('utf-8')
    body = dict((item.split('=') for item in body.split('&')))
    return rest_client.ResponseBody(resp, body)
