def change_attributes tagname, valuehash
      raise "Can not edit the attributes of tag: #{tagname}." unless ATTRIBUTE_TAGS.include? tagname
      tag = @report.at_css tagname
      valuehash.each do |key, value|
        tag.attributes["#{key}"].value = value
      end
    end
def change_attributes tagname, valuehash
      raise "Can not edit the attributes of tag: #{tagname}." unless ATTRIBUTE_TAGS.include? tagname
      tag = @report.at_css tagname
      valuehash.each do |key, value|
        tag.attributes["#{key}"].value = value
      end
    end
Set attributes of an report XML tag.
 Some of the QMRF XML tags have attributes to be edited. This applies to 6.1 to 6.4 and 7.1 to 7.4 see also: {OpenTox::QMRFReport::ATTRIBUTE_TAGS ATTRIBUTE_TAGS}.
 e.G. "Available information for the training set" at 6.2 of the report:
  <training_set_data cas="Yes" chapter="6.2" chemname="Yes" formula="Yes" help="" inchi="Yes" mol="Yes" name="Available information for the training set" smiles="Yes"/>
@example change_attributes
  report.change_attributes "training_set_data", {:inchi => "Yes", :smiles => "Yes"}
 @param [String] tagname Nodename e.g.: "training_set_data"
 @param [Hash] valuehash Key-Value Hash of tag attributes to change.
 @return [Error]  returns Error message if fails