def add(self, elem, replace=False):
        """Add a requirement.

        :param elem: a string or :class:`Requirement` instance.
        :param replace: if `True`, packages in the set with the same name will
            be removed first.
        """
        if isinstance(elem, text_type):
            elem = Requirement.coerce(elem)
        if replace and elem in self:
            self.remove(elem)
        super(Requirements, self).add(elem)
def _PostCreate(self):
    """Set the retention policy."""
    put_cmd = util.AWS_PREFIX + [
        '--region', self.region,
        'logs', 'put-retention-policy',
        '--log-group-name', self.name,
        '--retention-in-days', str(self.retention_in_days)
    ]
    vm_util.IssueCommand(put_cmd)