def __getitem__(self, key): return Counter.__getitem__(self, key)
def __getitem__(self, value): if value in self: return Counter.__getitem__(self, value) else: raise KeyError(value)
def __getitem__(self, key): return Counter.__getitem__(self, key) / self._total()
def __call__(self, value): return Counter.__getitem__(self, value)
def _total(self): total = 0 for key in self: total += Counter.__getitem__(self, key) return total