def get_attribute_ns(namespace, name)
      each_attribute() { |attribute|
        if name == attribute.name &&
          namespace == attribute.namespace()
          return attribute
        end
      }
      nil
    end
def get_attribute_ns(namespace, name)
      each_attribute() { |attribute|
        if name == attribute.name &&
          namespace == attribute.namespace()
          return attribute
        end
      }
      nil
    end
The +get_attribute_ns+ method retrieves a method by its namespace
 and name. Thus it is possible to reliably identify an attribute
 even if an XML processor has changed the prefix.

 Method contributed by Henrik Martensson