public Consumer<CommandSender> getAction() {
        return this.action;
    }
Makes an assertion about a condition.

<p>When used inside a command, command processing will be gracefully halted
if the condition is not true.</p>

@param condition the condition
@param failMsg the message to send to the player if the assertion fails
@throws CommandInterruptException if the assertion fails
helper/src/main/java/me/lucko/helper/command/CommandInterruptException.java