// @RubyLevelMethod(name="pack")
public RubyValue pack(RubyValue arg) {
String format = ((RubyString) arg).toString();
return ObjectFactory.createString(ArrayPacker.pack(this, format));
}
// @RubyLevelMethod(name="unpack")
public RubyValue unpack(RubyValue arg) {
RubyString format = ((RubyString) arg);
return ArrayPacker.unpack(toString(), format.toString());
}