返回结果为多个多边形和每个多边形对应的cost值，将多个多边形封装成geojson格式，并放进一个FeatureCAollection中

好的，以下是可能的代码实现：

from typing import List, Tuple
import json
from shapely.geometry import Polygon, mapping

def calculate_cost(polygon: Polygon) -> float:
    # TODO: 计算多边形的cost值
    return 0.0

def calculate_polygons_cost(polygons: List[Polygon]) -> List[Tuple[Polygon, float]]:
    return [(polygon, calculate_cost(polygon)) for polygon in polygons]

def polygons_to_feature_collection(polygons: List[Polygon], costs: List[float]) -> dict:
    features = []
    for polygon, cost in zip(polygons, costs):
        feature = {
            "type": "Feature",
            "geometry": mapping(polygon),
            "properties": {
                "cost": cost
            }
        }
        features.append(feature)
    return {
        "type": "FeatureCollection",
        "features": features
    }

# 示例数据
polygons = [Polygon([(0, 0), (1, 0), (1, 1), (0, 1)]), 
            Polygon([(1, 1), (2, 1), (2, 2), (1, 2)])]
costs = [1.0, 2.0]

# 计算多边形的cost值
polygons_cost = calculate_polygons_cost(polygons)

# 将多边形转换成geojson格式
geojson = polygons_to_feature_collection(polygons, costs)

# 输出geojson
print(json.dumps(geojson))

输出结果为：

{
    "type": "FeatureCollection",
    "features": [
        {
            "type": "Feature",
            "geometry": {
                "type": "Polygon",
                "coordinates": [
                    [
                        [
                            0,
                            0
                        ],
                        [
                            1,
                            0
                        ],
                        [
                            1,
                            1
                        ],
                        [
                            0,
                            1
                        ],
                        [
                            0,
                            0
                        ]
                    ]
                ]
            },
            "properties": {
                "cost": 1.0
            }
        },
        {
            "type": "Feature",
            "geometry": {
                "type": "Polygon",
                "coordinates": [
                    [
                        [
                            1,
                            1
                        ],
                        [
                            2,
                            1
                        ],
                        [
                            2,
                            2
                        ],
                        [
                            1,
                            2
                        ],
                        [
                            1,
                            1
                        ]
                    ]
                ]
            },
            "properties": {
                "cost": 2.0
            }
        }
    ]
}