def __init__(self,
                 environment='production',
                 api_base=None,
                 json=False,
                 _create_session=True):

        if api_base is None:
            try:
                Connection.__setattr__(self, 'api_base',
                                       API_BASES[environment])
            except KeyError:
                raise ClientError("Environment: {!r}, does not exist."
                                  .format(environment))
        else:
            Connection.__setattr__(self, 'api_base', api_base)

        Connection.__setattr__(self, 'json', json)

        if json:
            Connection.__setattr__(self, '_parser', JSONParser)
        else:
            Connection.__setattr__(self, '_parser', XMLParser)

        if _create_session:
            Connection.__setattr__(self, 'session', Session())
            self.session.headers['User-Agent'] = _generate_user_agent()
            if json:
                self.session.headers['Accept'] = ACCEPT_HEADERS['json']
Return a list of users that are in the specified group.
dataset/ETHPy150Open MediaMath/t1-python/terminalone/connection.py/Connection.__init__--crossover with--dataset/ETHPy150Open darcyliu/storyboard/boto/iam/connection.py/IAMConnection.get_group