model.begin()
model.exportPart(Part_2_doc, filename)
model.end()
assert os.path.exists(filename), "ERROR: Cannot export Part_2 to file {}".format(filename)
model.begin()
model.exportPart(Part_2_doc, filename)
model.end()
assert os.path.exists(filename), "ERROR: Cannot export Part_2 to file {}".format(filename)