Safe copy-paste using mixin

[drug via Digitalmars-d-learn]

I have code that is being duplicated in several places and I'd like to 
use mixins to simplify code maintenance but I failed to do it. For 
example https://github.com/drug007/hdf5-d-examples/blob/tmp/examples/aux.d

Lines 80-82, 91-93 and 99-101 are identical, how can I use mixin here?
I failed to do it because mixins demand declarations, not just code.