placesClient给出了持有nil值的错误，在阅读了googleplaces文档后我读到了这个声明:Thisclassshouldbeaccessedthroughthe[GMSPlacesClientsharedClient]method.我想知道如何实现sharedClient方法以便根据placesID搜索给定地点的信息？varplacesClient:GMSPlacesClient!funclookUpPlaceID(){letplaceID="ChIJPXw5JDZM6IAR4rTXaFQDGys"//WhatvalueshouldplacesClientbeholdi