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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def counter_multi(self, kvs, initial=None, delta=1, ttl=0):
 """Perform counter operations on multiple items :param kvs: Keys to operate on. See below for more options :param initial: Initial value to use for all keys. :param delta: Delta value for all keys. :param ttl: Expiration value to use for all keys :return: A :class:`~.MultiResult` containing :class:`~.ValueResult` values The `kvs` can be a: - Iterable of keys .. code-block:: python cb.counter_multi((k1, k2)) - A dictionary mapping a key to its delta .. code-block:: python cb.counter_multi({ k1: 42, k2: 99 }) - A dictionary mapping a key to its additional options .. code-block:: python cb.counter_multi({ k1: {'delta': 42, 'initial': 9, 'ttl': 300}, k2: {'delta': 99, 'initial': 4, 'ttl': 700} }) When using a dictionary, you can override settings for each key on a per-key basis (for example, the initial value). Global settings (global here means something passed as a parameter to the method) will take effect for those values which do not have a given option specified. """

        return _Base.counter_multi(self, kvs, initial=initial, delta=delta,
                                   ttl=ttl)