{
  "name": "num_interior_rings",
  "type": "function",
  "groups": ["GeometryGroup"],
  "description": "Returns the number of interior rings in a polygon or geometry collection, or NULL if the input geometry is not a polygon or collection.",
  "arguments": [ {"arg":"geometry","description":"input geometry"} ],
  "examples": [ { "expression":"num_interior_rings(geom_from_wkt('POLYGON((-1 -1, 4 0, 4 2, 0 2, -1 -1),(-0.1 -0.1, 0.4 0, 0.4 0.2, 0 0.2, -0.1 -0.1))'))", "returns":"1"}]
}