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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 download_blood_vessels():
 """data representing the bifurcation of blood vessels."""

    local_path, _ = _download_file('pvtu_blood_vessels/blood_vessels.zip')
    filename = os.path.join(local_path, 'T0000000500.pvtu')
    mesh = vtki.read(filename)
    mesh.set_active_vectors('velocity')
    return mesh