Proof of proveit.logic.booleans.quantification.existence.forall_implies_not_exists_not theorem

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

%proving forall_implies_not_exists_not

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