string|array option(string $key = null) Get the value of a command option

string anticipate(string $question, array $choices, string $default = null)

string askWithCompletion(string $question, array $choices, string $default = null)

void comment(string $string, null|int|string $verbosity = null) Write a

int callSilent(string $command, array $arguments = array()) Call another

void warn(string $string) Write a string as warning output.