def checkPermission(permission, object, interaction=None):
    """Return whether security policy allows permission on object.

    Arguments:
    permission -- A permission name
    object -- The object being accessed according to the permission
    interaction -- This Zope 3 concept has no equivalent in Zope 2,
        and is ignored.

    checkPermission is guaranteed to return True if permission is
    CheckerPublic or None.
    """
    if (permission in ('zope.Public', 'zope2.Public') or
        permission is None or permission is CheckerPublic):
        return True

    if isinstance(permission, StringTypes):
        permission = zapi.queryUtility(IPermission, unicode(permission))
        if permission is None:
            return False

    if getSecurityManager().checkPermission(permission.title, object):
        return True

    return False