@property<EOL><INDENT>def all_required_fields(self):<DEDENT>
def required_check(f):<EOL><INDENT>return not is_nullable_type(f.data_type) and not f.has_default<EOL><DEDENT>return self._filter_fields(required_check)<EOL>
Returns an iterator that traverses required fields in all super types
first, and then for this type.