code: func Any(err error, fn func(error) bool) (any bool) {
  	Walk(err, func(err error) bool {
  		any = fn(err)
  		return !any
  	})
  	return
  }
docs: // Any performs a Walk traversal of an error, returning true (and
  // short-circuiting) if the supplied filter function returns true for any
  // visited erorr.
  //
  // If err is nil, Any will return false.