Validate the resource

def validate(self):
        """Validate the resource"""
        if not self._resource.get('permissions'):
            self.permissions = self.default_permissions

        try:
            # update _resource so have default values from the schema
            self._resource = self.schema(self._resource)
        except MultipleInvalid as e:
            errors = [format_error(err, self.resource_type) for err in e.errors]
            raise exceptions.ValidationError({'errors': errors})

        yield self.check_service()
        yield self.check_unique()