Check this deploy.

def check(self, radl):
        """Check this deploy."""

        if not radl.get_system_by_name(self.id):
            raise RADLParseException("Invalid system id in the deploy.", line=self.line)

        if self.vm_number < 0:
            raise RADLParseException("Invalid number of virtual machines to deploy.",
                                     line=self.line)