import pandas as pd
import numpy as np

df = pd.DataFrame({
    "drop_id": [101, 102, 103, 104],
    "point": ["north", "south", "north", "south"],
    "material": ["leaves", "food", "food", "leaves"],
    "kg": [12., 8., 6., 10.],
    "bags": pd.array([3, 2, 1, 2], dtype="Int64"),
    "day": ["2026-10-01", "2026-10-01", "2026-10-02", "2026-10-02"],
})

lookup = pd.DataFrame({"point":["north","south"], "label":["North gate","South gate"]})
joined = df.merge(lookup, on="point", how="left", validate="many_to_one", indicator=True)
assert joined["_merge"].eq("both").all()
report = joined.groupby("label", sort=True)["kg"].sum(min_count=1)
assert np.isclose(report.sum(), df["kg"].sum())
print(report.index.tolist())
print(report.tolist())
print(float(report.sum()))