I have a very simple function that opens a file as shown in the example on mozilla

// fileHandle is a FileSystemFileHandle
// withWrite is a boolean set to true if write

async function verifyPermission(fileHandle, withWrite) {
  const opts = {};
  if (withWrite) {
    opts.mode = 'readwrite';
  }

  // Check if we already have permission, if so, return true.
  if (await fileHandle.queryPermission(opts) === 'granted') {
    return true;
  }

  // Request permission to the file, if the user grants permission, return true.
  if (await fileHandle.requestPermission(opts) === 'granted') {
    return true;
  }

  // The user did not grant permission, return false.
  return false;
}

but I keep getting an error saying that file.queryPermission is not a function. Here's my code:

let file = await window.showOpenFilePicker();
console.log(file.queryPermission({ mode: 'readwrite' }));

I've also tried putting the console.log in a .then but had the same result.