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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_assignment(self, assignment_id):
 """Get an assignment by ID and reformat the response. """

        try:
            response = self.mturk.get_assignment(AssignmentId=assignment_id)
        except ClientError as ex:
            if "does not exist" in str(ex):
                return None
            raise
        return self._translate_assignment(response["Assignment"])