code: func Sequence(funcs ...schema.CustomizeDiffFunc) schema.CustomizeDiffFunc {
  	return func(d *schema.ResourceDiff, meta interface{}) error {
  		for _, f := range funcs {
  			err := f(d, meta)
  			if err != nil {
  				return err
  			}
  		}
  		return nil
  	}
  }
docs: // Sequence returns a CustomizeDiffFunc that runs all of the given
  // CustomizeDiffFuncs in sequence, stopping at the first one that returns
  // an error and returning that error.
  //
  // If all functions succeed, the combined function also succeeds.