'Encode the facility and priority. You can pass in strings or
integers - if strings are passed, the facility_names and
priority_names mapping dictionaries are used to convert them to
integers.'

def encodePriority(self, facility, priority):

    if isinstance(facility, basestring):
        facility = self.facility_names[facility]
    if isinstance(priority, basestring):
        priority = self.priority_names[priority]
    return ((facility << 3) | priority)
