bounty将在2天后过期。回答此问题可获得+100声望奖励。Ky -希望引起更多人关注此问题。

在Xcode项目中安装POD时，我遇到了以下pod文件问题

Invalid `Podfile` file: undefined method `exists?' for File:Class

我没有尝试更新POD版本与brew upgrade cocoapods，也按照下面的链接
https://dev.to/retyui/fix-a-pod-install-error-undefined-method-exist-for-fileclass-react-native-24ke
但还是没办法。
请告诉我我做错了什么。
下面是我的POD文件

# Uncomment the next line to define a global platform for your project
# platform :ios, '9.0'

flutter_application_path = '../bmi_flutter'
    
load File.join(flutter_application_path, '.ios', 'Flutter', 'podhelper.rb')

target 'MixedNativeApp' do
  # Comment the next line if you don't want to use dynamic frameworks
  use_frameworks!
  install_all_flutter_pods(flutter_application_path)
  # Pods for MixedNativeApp

  target 'MixedNativeAppTests' do
    inherit! :search_paths
    # Pods for testing
  end

  target 'MixedNativeAppUITests' do
    # Pods for testing
  end

end