code: func (mounter *SafeFormatAndMount) FormatAndMount(source string, target string, fstype string, options []string) error {
  	// Don't attempt to format if mounting as readonly. Go straight to mounting.
  	for _, option := range options {
  		if option == "ro" {
  			return mounter.Interface.Mount(source, target, fstype, options)
  		}
  	}
  	return mounter.formatAndMount(source, target, fstype, options)
  }
docs: // FormatAndMount formats the given disk, if needed, and mounts it.
  // That is if the disk is not formatted and it is not being mounted as
  // read-only it will format it first then mount it. Otherwise, if the
  // disk is already formatted or it is being mounted as read-only, it
  // will be mounted without formatting.