def split_dataset(dataframe, set_size):
    """
    Splits a dataframe in two sets.

    :param dataframe: Dataframe to split.
    :param set_size: Size of the set located at the end. It is a number between 0 and 1.
    :return: The dataframe split in two sets.
    """
    if set_size:
        other_set_size = 1 - set_size
        split_point = int(len(dataframe) * other_set_size)

        set_keys = dataframe[:split_point]
        other_set_keys = dataframe[split_point:]

        return set_keys, other_set_keys

    return None, None