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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 tracebacks(score_matrix, traceback_matrix, idx):
 """Calculate the tracebacks for `traceback_matrix` starting at index `idx`. Returns: An iterable of tracebacks where each traceback is sequence of (index, direction) tuples. Each `index` is an index into `traceback_matrix`. `direction` indicates the direction into which the traceback "entered" the index. """

    return filter(lambda tb: tb != (),
                  _tracebacks(score_matrix,
                              traceback_matrix,
                              idx))