def __init__(self, package, version):
        """Construct a new requirement.

        :param package: the package name.
        :param version: a semver compatible version specification.
        """
        self.package = package
        self.version = version
        if self.version and not re.match(r"[<=>~]", version[:2]):
            self.version = "=={}".format(self.version)
def __enter__(self):
        """
        Syntax sugar which helps in celery tasks, cron jobs, and other scripts

        Usage:
            with Tenant.objects.get(schema_name='test') as tenant:
                # run some code in tenant test
            # run some code in previous tenant (public probably)
        """
        connection = connections[get_tenant_database_alias()]
        self._previous_tenant.append(connection.tenant)
        self.activate()

        return self