def purge(history_id, selector, metadata={}, countPurged=True):
    """Purge a Version from a Resources History

        If ``countPurged`` is ``True`` version numbering counts purged
        versions also. If ``False`` purged versiona are not taken into
        account.

        Purge the given version from the given history. The metadata
        passed may be used to store informations about the reasons of
        the purging.
        """
