def remove_attribute(namespace, key = nil)
      namespace, key = to_nns namespace, key
      attributes = @attributesByNamespace[namespace]
      return attributes.nil? ? nil : attributes.delete(key)
    end
def remove_attribute(namespace, key = nil)
      namespace, key = to_nns namespace, key
      attributes = @attributesByNamespace[namespace]
      return attributes.nil? ? nil : attributes.delete(key)
    end
remove_attribute(key)
   remove_attribute(namespace, key)

 Removes the attribute, whose name and namespace are specified.

 _key_:: name of the removed atribute
 _namespace_:: namespace of the removed attribute (equal to "", default namespace, by default)

 Returns the value of the removed attribute or +nil+ if it didn't exist.