如何在SwiftUI中使用其他结构/视图中的函数？

func calculateSum(a: Int, b: Int) -> Int {
    return a + b
}

import SwiftUI

struct ContentView: View {
    var body: some View {
        Text("Sum: \(calculateSum(a: 2, b: 3))")
    }
}

struct CustomView<Content: View>: View {
    let content: () -> Content
    
    init(@ViewBuilder content: @escaping () -> Content) {
        self.content = content
    }
    
    var body: some View {
        VStack {
            content()
            Button(action: {
                self.content().someFunction()
            }) {
                Text("Call Function")
            }
        }
    }
}

struct ContentView: View {
    var body: some View {
        CustomView {
            Text("Hello, World!")
                .onAppear {
                    print("View Appeared")
                }
        }
    }
}

class SharedModel: ObservableObject {
    @Published var count = 0
    
    func increment() {
        count += 1
    }
}

struct ContentView: View {
    @EnvironmentObject var sharedModel: SharedModel
    
    var body: some View {
        VStack {
            Text("Count: \(sharedModel.count)")
            Button(action: {
                sharedModel.increment()
            }) {
                Text("Increment")
            }
        }
    }
}