public static void printVariable(PrintWriter writer, String name, String value) {
    writer.print(name);
    writer.print(" = ");
    writer.print(value);
    writer.print('\n');
  }
retrieves the list of {@link CommandHandler}s setup in this environment
@return List of {@link CommandHandler}
samza-sql-shell/src/main/java/org/apache/samza/sql/client/cli/CliEnvironment.java