Slice a flat sequence of tokens into sequences tokens, with each
    inner sequence's length equal to the specified `length`, taking into account the requested
    sequence overlap.

    Parameters
    ----------
    sequence : list of object
        A flat list of tokens.
    length : int
        The length of each of the samples.
    pad_last : bool, default False
        Whether to pad the last sequence when its length doesn't align. If the last sequence's
        length doesn't align and ``pad_last`` is False, it will be dropped.
    pad_val : object, default
        The padding value to use when the padding of the last sequence is enabled. In general,
        the type of ``pad_val`` should be the same as the tokens.
    overlap : int, default 0
        The extra number of items in current sample that should overlap with the
        next sample.

    Returns
    -------
    List of list of tokens, with the length of each inner list equal to `length`.

def slice_sequence(sequence, length, pad_last=False, pad_val=C.PAD_TOKEN, overlap=0):
    """Slice a flat sequence of tokens into sequences tokens, with each
    inner sequence's length equal to the specified `length`, taking into account the requested
    sequence overlap.

    Parameters
    ----------
    sequence : list of object
        A flat list of tokens.
    length : int
        The length of each of the samples.
    pad_last : bool, default False
        Whether to pad the last sequence when its length doesn't align. If the last sequence's
        length doesn't align and ``pad_last`` is False, it will be dropped.
    pad_val : object, default
        The padding value to use when the padding of the last sequence is enabled. In general,
        the type of ``pad_val`` should be the same as the tokens.
    overlap : int, default 0
        The extra number of items in current sample that should overlap with the
        next sample.

    Returns
    -------
    List of list of tokens, with the length of each inner list equal to `length`.

    """
    if length <= overlap:
        raise ValueError('length needs to be larger than overlap')

    if pad_last:
        pad_len = _slice_pad_length(len(sequence), length, overlap)
        sequence = sequence + [pad_val] * pad_len
    num_samples = (len(sequence) - length) // (length - overlap) + 1

    return [sequence[i * (length - overlap): ((i + 1) * length - i * overlap)]
            for i in range(num_samples)]