multiple instances and (e.g.) vhdl_code

Is there a template string for getting an identifier for the current 
instance when using vhdl_code?

That is, I want the name of the function inside the vhdl code to be 
different for each call to the instance constructor. So the vhdl_code 
could look something like:
FOO_BAR.vhdl_code = '''
foo_bar_$this_id: entity work.SOME_BLOCK(MyHDL)
...
'''

I'm currently working around it with a module local list of allocated 
ids and creating a new one each time. This works, but is not very neat.

Cheers,

Henry

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