what to do when node was already in close in a 2a algorithm

114 if node_successor is on the CLOSED list but the existing one is as good 
2   or better then discard this successor and continue
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1Get the square on the open list which has the lowest score. Let’s call this square S.
2Remove S from the open list and add S to the closed list.
3For each square T in S’s walkable adjacent tiles:
4If T is in the closed list: Ignore it.
5If T is not in the open list: Add it and compute its score.
6If T is already in the open list: Check if the F score is lower when we use the current generated path to get there. If it is, update its score and update its parent as well.
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