jcreus/sympy — comment on commit d1155d4bfe9d5be7f78930b9d9ee5a180926e77f
File: sympy/utilities/runtests.py line 628
By jcreus:

Do you mean "funcs = [f for f in funcs if getattr(f, '_slow', False)]"?

It "filters" the values of the list of functions to only save those which have a _slow=True attribute (this attribute is set by the @SLOW decorator.