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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 position(self, partition):
 """Get the offset of the next record that will be fetched Arguments: partition (TopicPartition):
 Partition to check Returns: int: Offset """

        if not isinstance(partition, TopicPartition):
            raise TypeError('partition must be a TopicPartition namedtuple')
        assert self._subscription.is_assigned(partition), 'Partition is not assigned'
        offset = self._subscription.assignment[partition].position
        if offset is None:
            self._update_fetch_positions([partition])
            offset = self._subscription.assignment[partition].position
        return offset