#This file is distributed under the terms of the GNU General Public license.
#Copyright (C) 1999 Aloril (See the file COPYING for details).

class Knowledge:
    def __init__(self):
        self.knowings={}
    def add(self, what, key, value):
        if what not in self.knowings:
            self.knowings[what] = {}
        self.knowings[what][key] = value
    def remove(self, what, key):
        if what in self.knowings:
            del self.knowings[what][key]
    def get(self, what, key=None):
        if not key:
            return self.knowings.get(what, {})
        else:
            if what not in self.knowings:
                return None
            return self.knowings[what][key]
    def __str__(self):
        s="<know: " + str(self.knowings)
        return s+">\n"