def __init__(self, repository_url=None, user=None, password=None, verify_ssl=True):
        self._verify_ssl = verify_ssl

        if repository_url:
            self._repository_url = repository_url
        else:
            self._repository_url = os.environ.get('REPOSITORY_URL', self.DEFAULT_REPOSITORY_URL)

        self._session = requests.session()

        if not user:
            user = os.environ.get('REPOSITORY_USER')

        if user:
            if not password:
                try:
                    password = os.environ['REPOSITORY_PASSWORD']
                except KeyError:
                    logger.error('Repository password not specified. Please specify repository password in environment'
                                 ' variable "REPOSITORY_PASSWORD"')
            self._session.auth = (user, password)
Check to see if a table exists.
dataset/ETHPy150Open stardust85/repositorytools/repositorytools/lib/repository.py/NexusRepositoryClient.__init__--crossover with--dataset/ETHPy150Open tylertreat/BigQuery-Python/bigquery/client.py/BigQueryClient.check_table