class MultiPolygon(polygons)
The MultiPolygon constructor takes a sequence of exterior ring and hole list tuples: [((a1, …, aM), [(b1, …, bN), …]), …].
复合多边形构造函数接收外部线环和内部线环（洞）两组序列元祖。
More clearly, the constructor also accepts an unordered sequence of Polygon instances, thereby making copies.
构造函数同样也接收线实例的无序序列，从而得到一个副本。
>>> polygons = MultiPolygon([polygon, s, t])
>>> len(polygons.geoms)
3(Source code, png, hires.png, pdf)
that is invalid because its members touch at an infinite number of points (along a line).图7. 左边是一个有2个成员的有效的复合多边形，右边是一个无效的复合多边形，因为它的成员在无限多的点（沿着一条线）相接触。
Its x-y bounding box is a (minx, miny, maxx, maxy) tuple.
其边界是一个元组（minx, miny, maxx, maxy）。
>>> polygons.bounds
(-1.0, -1.0, 2.0, 2.0)Its members are instances of Polygon and are accessed via the geoms property.
其成员是Polygon实例，可以通过geoms属性访问。
>>> len(polygons.geoms)
3