Validate the JSON schema. Return list of errors.

def validate_json_schema(self):
        """Validate the JSON schema. Return list of errors."""
        errors = []

        for work in self:
            for task in work:
                if not task.get_results().validate_json_schema():
                    errors.append(task)
            if not work.get_results().validate_json_schema():
                errors.append(work)
        if not self.get_results().validate_json_schema():
            errors.append(self)

        return errors