This code deletes all nodes whose info field contains the value x. Please modify the code to delete the only first value of x : ( maybe we need to add one line )  ( with explanation for each line if possible) many thanks.

An integer sequence {40,28,6,72，100,3,54,1,80,91,38}, please create a BST according to the sequence, then delete node 72 and give all possible deletion results

def upgrade_stations(threshold: int, num_bikes: int,                     stations: List["Station"]) -> int:    """Modify each station in stations that has a capacity that is less than    threshold by adding num_bikes to the capacity and bikes available counts.    Modify each station at most once.     Return the total number of bikes that were added to the bike share network.     Precondition: num_bikes >= 0