`IndexError` in `shapely.geometry.shape` when parsing a MultiPolygon with some empty members

Expected behavior and actual behavior.

Create a MultiPolygon.

Steps to reproduce the problem.

I think this is valid GeoJSON, but shapely errors when trying to convert it.

import shapely.geometry
data = {
    "type": "MultiPolygon",
    "coordinates": [
        [],
        [[[0, 0],
          [1, 0],
          [1, 1],
          [0, 1],
          [0, 0]]]
    ]
}

shapely.geometry.shape(data)

That raises with

---------------------------------------------------------------------------
IndexError                                Traceback (most recent call last)
Input In [3], in <cell line: 13>()
      1 data = {
      2     "type": "MultiPolygon",
      3     "coordinates": [
   (...)
     10     ]
     11 }
---> 13 shapely.geometry.shape(data)

File ~/src/stac-utils/stac-geoparquet/.venv/lib/python3.8/site-packages/shapely/geometry/geo.py:118, in shape(context)
    116     return MultiLineString(ob["coordinates"])
    117 elif geom_type == "multipolygon":
--> 118     return MultiPolygon(ob["coordinates"], context_type='geojson')
    119 elif geom_type == "geometrycollection":
    120     geoms = [shape(g) for g in ob.get("geometries", [])]

File ~/src/stac-utils/stac-geoparquet/.venv/lib/python3.8/site-packages/shapely/geometry/multipolygon.py:62, in MultiPolygon.__init__(self, polygons, context_type)
     60     geom, n = geos_multipolygon_from_polygons(polygons)
     61 elif context_type == 'geojson':
---> 62     geom, n = geos_multipolygon_from_py(polygons)
     63 self._set_geom(geom)
     64 self._ndim = n

File ~/src/stac-utils/stac-geoparquet/.venv/lib/python3.8/site-packages/shapely/geometry/multipolygon.py:146, in geos_multipolygon_from_py(ob)
    143 L = len(ob)
    144 assert L >= 1
--> 146 N = len(ob[0][0][0])
    147 assert N == 2 or N == 3
    149 subs = (c_void_p * L)()

IndexError: list index out of range

Operating system

Linux

Shapely version and provenance

1.8.2 from PyPI

Start by running the GeoJSON reproducer through shapely.geometry.shape and trace the MultiPolygon path shown in geometry/geo.py and geometry/multipolygon.py, especially geos_multipolygon_from_py. Check how empty members are handled and add regression coverage for this input. Done means the example no longer raises IndexError when parsed.