def remove_indices(indices, inds_to_be_rm):
    """
    Convert some bound indices to free ones.

    The conversion goes as: inds_to_be_rm[i] -> -1 - i

    Args:
        indices ([int]): list in which the conversion is to be done
        inds_to_be_rm ([int]): list of the indices to be made free in order

    Return:
       A list of the changed indices.
    """
    return [ind if ind not in inds_to_be_rm
            else -inds_to_be_rm.index(ind)-1
            for ind in indices]