KozaApp.schema is never initialized

[ptgolden]

I'm familiarizing myself with the codebase and cleaning up some type annotations, and I've noticed something off with the write method in the KozaApp class. Whether or not the class validates depends on the presence of the schema attribute in the class instance:

koza/src/koza/app.py

Lines 151 to 154 in fceafe5

	def write(self, *entities):
	# If a schema/validator is defined, validate before writing
	# if self.validate:
	if hasattr(self, 'schema'):

However, the code that sets that attribute is commented out in the __init__ method:

koza/src/koza/app.py

Lines 52 to 57 in fceafe5

	if schema:
	# self.validate = True
	# self.schema = schema
	# self.node_type = node_type
	# self.edge_type = edge_type
	self.converter = KGXConverter()

It looks like it was removed in a0ba9cb. Is it intentional that that block of code in write() should never run?