def element_for_attribute(name, namespace='')
      val = instance_values[name]
      return "" if val == nil
      "<%s:%s val='%s'/>" % [namespace, Axlsx::camel(name, false), val]
    end
def element_for_attribute(name, namespace='')
      val = instance_values[name]
      return "" if val == nil
      "<%s:%s val='%s'/>" % [namespace, Axlsx::camel(name, false), val]
    end
Note: move this to Axlsx module if we find the smae pattern elsewhere.