refactor 'map_sel_thms' and 'set_sel_thms'
refactor 'map_sel_thms' and 'set_sel_thms'

MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle