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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 get_FORCE_SETS_lines(dataset, forces=None):
 """Generate FORCE_SETS string See the format of dataset in the docstring of Phonopy.set_displacement_dataset. Optionally for the type-1 (traditional) format, forces can be given. In this case, sets of forces are unnecessary to be stored in the dataset. """


    if 'first_atoms' in dataset:
        return _get_FORCE_SETS_lines_type1(dataset, forces=forces)
    elif 'forces' in dataset:
        return _get_FORCE_SETS_lines_type2(dataset)