```ruby
module Fastlane
  module Helper
    class YarnHelper
      # class methods that you define here become available in your action
      # as `Helper::YarnHelper.your_method`

      attr_accessor :task
      attr_accessor :commands
      attr_accessor :package_path

      def initialize(package_path: nil)
        self.package_path = package_path

        if self.package_path
          Dir.chdir(File.dirname(self.package_path))
        end
      end

      # Run a certain action
      def trigger(command: nil, task: nil, print_command: true, print_command_output: true)

        command = ["yarn", command, task].compact.join(" ")
        Action.sh(command, print_command: print_command, print_command_output: print_command_output)
      end

      def check_install
        check_package

        UI.message("Checking yarn install and dependencies")
        begin
          Action.sh("yarn", print_command: true, print_command_output: true)
        rescue Errno::ENOENT => e
          UI.error("Yarn not installed, please install with Homebrew or npm.")
          raise e
        end

      end

      def check_package()
        UI.message("Checking for valid package.json")
        unless self.package_path.nil?
          package_path = 'package.json'
        end

        unless File.exists?(package_path)
          UI.error("Could not find package.json")
          raise Errno::ENOENT
        end
      end
    end
  end
end
```

Fix warning for conflicting chdir
user
```ruby
module Fastlane
  module Helper
    class YarnHelper
      # class methods that you define here become available in your action
      # as `Helper::YarnHelper.your_method`

      attr_accessor :task
      attr_accessor :commands
      attr_accessor :package_path
      attr_accessor :yarn

      def initialize(package_path: nil)
        self.package_path = package_path

        if self.package_path
          self.yarn = "cd #{File.dirname(self.package_path)} && yarn"
        else
          self.yarn = "yarn"
        end
      end

      # Run a certain action
      def trigger(command: nil, task: nil, print_command: true, print_command_output: true)

        command = [self.yarn, command, task].compact.join(" ")
        Action.sh(command, print_command: print_command, print_command_output: print_command_output)
      end

      def check_install
        check_package

        UI.message("Checking yarn install and dependencies")
        begin
          Action.sh(self.yarn, print_command: true, print_command_output: true)
        rescue Errno::ENOENT => e
          UI.error("Yarn not installed, please install with Homebrew or npm.")
          raise e
        end

      end

      def check_package()
        UI.message("Checking for valid package.json")

        if self.package_path.nil?
          package_path = 'package.json'
        else
          package_path = self.package_path
        end

        unless File.exists?(package_path)
          UI.error("Could not find package.json")
          raise Errno::ENOENT
        end
      end
    end
  end
end
```
assistant