@classmethod<EOL><INDENT>def apply_iter(cls, rows, mapping, resolver, scope=None):<DEDENT>
mapper = cls(mapping, resolver, scope=scope)<EOL>for row in rows:<EOL><INDENT>_, data = mapper.apply(row)<EOL>yield data<EOL><DEDENT>
Given an iterable ``rows`` that yield data records, and a
        ``mapping`` which is to be applied to them, return a tuple of
        ``data`` (the generated object graph) and ``err``, a validation
        exception if the resulting data did not match the expected schema.