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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def create_or_update_group(self, name, policies=None, mount_point=DEFAULT_MOUNT_POINT):
 """ Create or update LDAP group policies. Supported methods: POST: /auth/{mount_point}/groups/{name}. Produces: 204 (empty body) :param name: The name of the LDAP group :type name: str | unicode :param policies: List of policies associated with the group. This parameter is transformed to a comma-delimited string before being passed to Vault. :type policies: list :param mount_point: The "path" the method/backend was mounted on. :type mount_point: str | unicode :return: The response of the create_or_update_group request. :rtype: requests.Response """

        if policies is None:
            policies = []
        if not isinstance(policies, list):
            error_msg = '"policies" argument must be an instance of list or None, "{policies_type}" provided.'.format(
                policies_type=type(policies),
            )
            raise exceptions.ParamValidationError(error_msg)

        params = {
            'policies': ','.join(policies),
        }
        api_path = '/v1/auth/{mount_point}/groups/{name}'.format(
            mount_point=mount_point,
            name=name,
        )
        return self._adapter.post(
            url=api_path,
            json=params,
        )