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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(self, counter_name, default=0):
 """Get the current counter value. Args: counter_name: name of the counter in string. default: default value in int if one doesn't exist. Returns: Current value of the counter. """

    return self._state.counters_map.get(counter_name, default)