Districts: for a precinct, county, town, city (place) or ZIP, the congressional, state senate and state house
districts it falls in; for a district, the precincts, counties, towns, cities or ZIPs inside it (filter with
`level`, e.g. 'precinct'). A city ('us:place:1714000') also lists its counties. A ZIP ('us:zcta:07102') lists the
cities, counties, towns, precincts and districts it overlaps. Ask for `level='zcta'` on a city, county, town or
district to list the ZIP codes in it.
`weight` is the share of the smaller unit's 2020 population inside the other (for a ZIP, the share of the ZIP's
residents in each unit; 0 for parts with land but no residents). relation 'within' means wholly inside (1.0),
'overlaps' means split, 'approximate' means the unit was too small to contain any 2020 block's internal point and
was placed by the nearest block. Use min_weight to drop slivers. ZCTAs approximate USPS ZIP Codes.