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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 add_keyed(self, value, key, date=None, return_value=False):
 """Add keyed metrics data to collection. Args: value (str):
 The value of the metric. key (str):
 The key value for keyed metrics. date (str, optional):
 The optional date of the metric. return_value (bool, default:False):
 Tell the API to return the updates metric value. Return: dict: If return_value is True a dict with the current value for the time period is returned. """

        return self.add(value, date, return_value, key)