Proof of proveit.logic.booleans.implication.left_from_iff theorem

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

%proving left_from_iff

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

%qed

proveit.logic.booleans.implication.left_from_iff has been proven.

	step type	requirements	statement
0	generalization	1	⊢
1	modus ponens	2, 3	,  ⊢
2	instantiation	4, 5	⊢
	: , :
3	assumption		⊢
4	theorem		⊢
	proveit.logic.booleans.implication.iff_implies_left
5	assumption		⊢