def gen(self):
        """
        Generate stable LogicalIds based on the prefix and given data. This method ensures that the logicalId is
        deterministic and stable based on input prefix & data object. In other words:

            logicalId changes *if and only if* either the `prefix` or `data_obj` changes

        Internally we simply use a SHA1 of the data and append to the prefix to create the logicalId.

        NOTE: LogicalIDs are how CloudFormation identifies a resource. If this ID changes, CFN will delete and
              create a new resource. This can be catastrophic for most resources. So it is important to be *always*
              backwards compatible here.


        :return: LogicalId that can be used to construct resources
        :rtype string
        """

        data_hash = self.get_hash()
        return "{prefix}{hash}".format(prefix=self._prefix, hash=data_hash)