Proof of proveit.logic.sets.enumeration.in_enum_set_is_bool theorem

import proveit
theory = proveit.Theory() # the theorem's theory

%proving in_enum_set_is_bool

With these allowed/disallowed theorem/theory presumptions (e.g., to avoid circular dependencies), we begin our proof of
in_enum_set_is_bool:
(see dependencies)

in_enum_set_is_bool may now be readily provable (assuming required theorems are usable).  Simply execute "%qed".