Verification Academy

Hi everyone:
I have a syntax problem when i read VMM source code. Here is the code segment:

(*_vcs_vmm_class=1*)
class vmm_sb_ds_registeration;
  bit is_in;
  bit is_out;
  vmm_sb_ds::ordering_eorder;
endclass

So, what's the meaning of the "(*_vcs_vmm_class=1*)", and why use it before the class vmm_sb_ds_registeration?

I looked for the IEEE 1800-2009, only konws the syntax above is attributes, but do not understand is meaning, and how to use it properly.

Could anyone tell me this question and give me a application example? Thanks a lot!