code: def _get_constraints(self):
          
          num_edges = len(self.edges)
          for k in range(num_edges):
              for i in range(num_edges):
                  # add to constraints if i shared an edge with k
                  if k != i and self.edges[k].is_adjacent(self.edges[i]):
                      self.edges[k].neighbors.append(i)
docs: Get neighboring edges for each edge in the edges.