'Returns a single user.
Args:
user_id:
The id of the user to retrieve. [Optional]
screen_name:
The screen name of the user for whom to return results for.
Either a user_id or screen_name is required for this method.
[Optional]
include_entities:
The entities node will be omitted when set to False.
[Optional]
Returns:
A twitter.User instance representing that user'

def GetUser(self, user_id=None, screen_name=None, include_entities=True):

    url = ('%s/users/show.json' % self.base_url)
    parameters = {}
    if user_id:
        parameters['user_id'] = user_id
    elif screen_name:
        parameters['screen_name'] = screen_name
    else:
        raise TwitterError({'message': 'Specify    at    least    one    of    user_id    or    screen_name.'})
    if (not include_entities):
        parameters['include_entities'] = 'false'
    resp = self._RequestUrl(url, 'GET', data=parameters)
    data = self._ParseAndCheckTwitter(resp.content.decode('utf-8'))
    return User.NewFromJsonDict(data)
