def merge_cluster_pair(clusts, gap_ind):
    """
    Merge two clusters which boarder a gap
    
    Notes:
    * the new cluster will be a continuous range of indices
    * The gap index "i" will merge clusters "i" and "i+1"
    """
    
    # Get the clusters up to the gap index
    new_clusts = clusts[:gap_ind].copy()
    
    # Add cluster as a range of indices from the merged clusters
    new_clusts.append(list(range(clusts[gap_ind][0],clusts[gap_ind+1][-1]+1)))
    
    # Add the remaining clusters
    new_clusts.extend(clusts[gap_ind+2:])
    
    return new_clusts