You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: GCO_SetNeighbors.m
    path of file: ./repos/microshift_compression/matlab code/Toolkits/gco-v3.0/matlab
    
    the code of the file until where you have to start completion: function GCO_SetNeighbors(Handle,Weights)
% GCO_SetNeighbors   Set (weighted) pairwise connectivity of all sites.
%     GCO_SetNeighbors(Handle,Weights) determines which sites are neighbors
%     and thereby have a SmoothCost associated with them. Weights is a

    
function GCO_SetNeighbors(Handle,Weights)
% GCO_SetNeighbors   Set (weighted) pairwise connectivity of all sites.
%     GCO_SetNeighbors(Handle,Weights) determines which sites are neighbors
%     and thereby have a SmoothCost associated with them. Weights is a
%     sparse NumSites-by-NumSites matrix, where Weights(i,j) > 0 indicates 
%     that sites i and j are neighbors. If Weights is a 0-1 matrix, smooth
%     costs are spatially invariant. See SetSmoothCost for more.
%
%     SetNeighbors cannot be called after Expansion. 
%     Note: only the upper-triangular area of Weights is consulted 
%           because the connectivity is undirected. 

GCO_LoadLib();
NumSites = gco_matlab('gco_getnumsites',Handle);
if (size(Weights) ~= [ NumSites NumSites ])
    error('Neighbors must be of size [ NumSites NumSites ]');
end