[Python] How to assign column values based on another column iteratively with Polars

For these two dfs, I want to check for each i in df1["TS"] if df["TS"] == df1["TS}, then assign the value in "Dr" that corresponds to i to the "mmsi" column:

df = pl.DataFrame({"TS": [1, 2, 3, 4, 5, 6, 7], "mmsi":[11,12,13,14,15,16,17]})


df1 = pl.DataFrame({
"TS": [4, 6, 7],
"Dr": [21,22,23]})


I want the output of df["mmsi"] to be: [11,12,13,21,15,22,23]

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