Function alter_table_add_columns 

pub async fn alter_table_add_columns(
    configuration: &Configuration,
    id: &str,
    alter_table_add_columns_request: AlterTableAddColumnsRequest,
    delimiter: Option<&str>,
) -> Result<AlterTableAddColumnsResponse, Error<AlterTableAddColumnsError>>

Add new columns to table id using SQL expressions or default values.