def METHOD_NAME(self, validate=False, dry_run=False):
    """
    Update the data associated with this snapshot by querying EC2.
    :type validate: bool
    :param validate: By default, if EC2 returns no data about the
                     snapshot the update method returns quietly.  If
                     the validate param is True, however, it will
                     raise a ValueError exception if no data is
                     returned from EC2.
    """
    rs = self.connection.get_all_snapshots([self.id], dry_run=dry_run)
    if len(rs) > 0:
        self._update(rs[0])
    elif validate:
        raise ValueError('%s is not a valid Snapshot ID' % self.id)
    return self.progress