rem = fact

        This
        self.facts.remove(fact)


        Left

        for f in self.facts: # for each fact
            if fact in f.supports_facts: # if this fact supports retracted fact
                f.supports_facts.remove(fact) # remove retracted from supported list for that fact

        for r in self.rules:
            if fact in r.supports_facts:
                r.supports_facts.remove(fact)

        Right
        for f in self.facts:
            print(len(f.supported_by))
            for fr in f.supported_by: # for fr pair
                if fact in fr: # if that fr pair contains this fact
                    f.remove(fr) # rm that pair
            if f.supported_by == []: # if afterwards there is no more support
                self.kb_retract(f) # retract that fact

        for r in self.rules:
            if r.asserted: continue
            for fr in r.supported_by:
                if fact in fr:
                    r.remove(fr)
            if r.supported_by == []:
                self.rules.remove(r)