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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 from_detections_assignment(detections_1, detections_2, assignments):
 """ Creates traces out of given assignment and cell data. """

        traces = []

        for d1n, d2n in six.iteritems(assignments):
            # check if the match is between existing cells
            if d1n < len(detections_1) and d2n < len(detections_2):
                traces.append(Trace(detections_1[d1n], detections_2[d2n]))

        return traces