getPlan method
Will get a collection of PcoServicesPlan objects (expecting one)
using a path like this: https://api.planningcenteronline.com/services/v2/people/1/plan_people/1/plan
Implementation
Future<PcoCollection<PcoServicesPlan>> getPlan(
{PcoServicesPlanQuery? query}) async {
query ??= PcoServicesPlanQuery();
var url = '$apiEndpoint/plan';
return PcoCollection.fromApiCall<PcoServicesPlan>(url,
query: query, apiVersion: apiVersion);
}