fix q16

tpch/queries/q16.py

@@ -11,15 +11,14 @@ def query(part_ds: FrameT, partsupp_ds: FrameT, supplier_ds: FrameT) -> FrameT:
     ).select(nw.col("s_suppkey"), nw.col("s_suppkey").alias("ps_suppkey"))
 
     return (
-        # not Done
         part_ds.join(partsupp_ds, left_on="p_partkey", right_on="ps_partkey")
         .filter(nw.col("p_brand") != var1)
         .filter(~nw.col("p_type").str.contains("MEDIUM POLISHED*"))
         .filter(nw.col("p_size").is_in([49, 14, 23, 45, 19, 3, 36, 9]))
         .join(supplier, left_on="ps_suppkey", right_on="s_suppkey", how="left")
         .filter(nw.col("ps_suppkey_right").is_null())
         .group_by("p_brand", "p_type", "p_size")
-        .agg(nw.col("ps_suppkey").n_unique().alias("supplier_cnt"))
+        .agg(nw.col("ps_suppkey").unique().len().alias("supplier_cnt"))
         .sort(
             by=["supplier_cnt", "p_brand", "p_type", "p_size"],
             descending=[True, False, False, False],