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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 diff_texts(a, b, filename):
 """Return a unified diff of two strings."""

    a = a.splitlines()
    b = b.splitlines()
    return difflib.unified_diff(a, b, filename, filename,
                                "(original)", "(refactored)",
                                lineterm="")