def alloc_to_share_ratio(share, total_shares, allocation, total_alloc):
    """
    Calculate the allocation to share (advantage) ratio given to a region or group.

    Parameters
    ----------
        share : int
            The proportion to be checked.

        total_shares : int
            The total amount of shares.

        allocation : int
            The share of allocations given to the region or group.

        total_alloc : int
            The number of allocations to provide.

    Returns
    -------
        asr : float
            The ratio of the allocations the region or group received to their proportion of the original shares.
    """
    return 1.0 * (allocation / total_alloc) / (share / total_shares)