'Set value of a counter by counter key'

def value(self, key, value=1):

    if isinstance(key, six.string_types):
        key = (key,)
    assert isinstance(key, tuple), u'event    key    type    error'
    if (key not in self.counters):
        self.counters[key] = self.cls()
    self.counters[key].value(value)
    return self
