def cleanpath(path)
      path = Pathname.new(path) unless path.is_a?(Pathname)
      pathname(path.cleanpath.to_s)
    end
def cleanpath(path)
      path = Pathname.new(path) unless path.is_a?(Pathname)
      pathname(path.cleanpath.to_s)
    end
Like `Pathname#cleanpath`, but normalizes Windows paths to always use
 backslash separators. Normally, `Pathname#cleanpath` actually does the
 reverse -- it will convert backslashes to forward slashes, which can break
 `Pathname#relative_path_from`.

 @param path [String, Pathname]
 @return [Pathname]