# File rexml/element.rb, line 1511
    def []=( name, value )
      if value.nil?
	attr = get_attribute name
	delete attr
	return
      end
      value = Attribute.new(name, value) unless value.kind_of? Attribute
      value.element = @element
      old_attr = fetch value.name, nil
      if old_attr.nil?
	store(value.name, value)
      elsif old_attr.kind_of? Hash
	old_attr[value.prefix] = value
      elsif old_attr.prefix != value.prefix
	store value.name, { old_attr.prefix	=> old_attr,
	  value.prefix		=> value }
      else
	store value.name, value
      end
      return @element
    end