# File rexml/source.rb, line 9
    def SourceFactory::create_from(arg)
      if arg.kind_of? String
        Source.new(arg)
      elsif arg.respond_to? :read and
            arg.respond_to? :readline and
            arg.respond_to? :nil? and
            arg.respond_to? :eof?
        IOSource.new(arg)
      elsif arg.kind_of? Source
        arg
      else
        raise "#{arg.class} is not a valid input stream.  It must walk \n"+
          "like either a String, an IO, or a Source."
      end
    end