我从一个传入的POST请求中接收到一些geojson，我想用geopandas计算它的总平方英里。但由于某种原因，Geopandas给了我一个错误：

"geometry": shape(feature["geometry"]) if feature["geometry"] else None
                                              ~~~~~~~^^^^^^^^^^^^
TypeError: string indices must be integers, not 'str'

我的Python代码：

import functions_framework
import geopandas as gpd
from shapely.geometry import shape

@functions_framework.http
def calculate_sq_miles(request):

    geojson_dict = request.get_json()

    # Create a geopandas DataFrame from the dictionary
    df = gpd.GeoDataFrame.from_features(geojson_dict)

    # Calculate the area of the polygon in square meters
    area = df.geometry.area

    # Convert the area from square meters to square miles
    area_in_square_miles = area / 2589988.1103

    return area_in_square_miles

geojson输入数据：

{"type":"Feature","properties":{},"geometry":{"type":"Polygon","coordinates":[[30.377407078486545,-112.12297812500002],[42.68629683675748,-112.12297812500002],[42.68629683675748,-126.71282187500002],[30.377407078486545,-126.71282187500002],[30.377407078486545,-112.12297812500002]]}}

起初我以为geojson输入格式不正确，但我没有看到任何问题。我做错了什么？