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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 get(self, time, interpolate='previous'):
 """Get the value of the time series, even in-between measured values. """

        try:
            getter = self.getter_functions[interpolate]
        except KeyError:
            msg = (
                "unknown value '{}' for interpolate, "
                "valid values are in [{}]"
            ).format(interpolate, ', '.join(self.getter_functions))
            raise ValueError(msg)
        else:
            return getter(time)