SuperCollider * marking the constructor method is not expected - syntax

Question

I tried to create a Class and the constructor always gave me a Syntax Error about the *new method then I just copied the Example from the documentation:
MyClass {
// this is a normal constructor method
*new { | arga, argb, argc |
^super.new.init(arga, argb, argc)
}
init { | arga, argb, argc |
// do initiation here
}
}
and still got this:
ERROR: syntax error, unexpected '*', expecting '}'
in interpreted text
line 6 char 5:
*new { | arga, argb, argc |
^
^super.new.init(arga, argb, argc)
-----------------------------------
ERROR: Command line parse failed
-> nil
From my own class i get the same error concerning the constructor. Where am I wrong?

Answer 1

If you check out the Writing Classes helpfile, there's a bit at the top that's easy to miss about where to save your classes.
https://depts.washington.edu/dxscdoc/Help/Guides/WritingClasses.html
NOTE: Class definitions are statically compiled when you launch
SuperCollider or "recompile the library." This means that class
definitions must be saved into a file with the extension .sc, in a
disk location where SuperCollider looks for classes. Saving into the
main class library (SCClassLibrary) is generally not recommended. It's
preferable to use either the user or system extension directories.
Platform.userExtensionDir; // Extensions available only to your user account
Platform.systemExtensionDir; // Extensions available to all users on the machine
It is not possible to enter a class definition into an interpreter
window and execute it.
The the Save As Extension option under the file menu. Then recompile the interpretter and try using your class.