Create transitive predicates in Python.

transitivity

def transitivePredicate(db):
	def predicate(a, b):
		pool = db.get(a)
		if not pool:
			return False
		if b in pool:
			return True
		for ent in pool:
			if predicate(ent, b):
				return True
		return False
	return predicate

isTaller = transitivePredicate({
	"me": ["you"],
	"you": ["him"],
	"him": ["that", "it"],
	"it": ["that"],
	"that": ["this"],
})

assert isTaller("me", "you")
assert isTaller("you", "him")
assert isTaller("me", "him")
assert isTaller("you", "this")
assert not isTaller("you", "me")
assert not isTaller("that", "you")	
assert isTaller("it", "this")
assert isTaller("you", "it")