def validate_config(config)
        raise ConfigurationError, 'configuration is nil, did you forget to configure the gem?' unless config
        raise ConfigurationError, 'api_host must be configured' unless string_present? config.api_host
        raise ConfigurationError, 'api_user must be configured' unless string_present? config.api_user
        raise ConfigurationError, 'api_password must be configured' unless string_present? config.api_password