def delete_namespace namespace="xmlns"
      namespace = "xmlns:#{namespace}" unless namespace == 'xmlns'
      attribute = attributes.get_attribute(namespace)
      attribute.remove unless attribute.nil?
      self
    end
def delete_namespace namespace="xmlns"
      namespace = "xmlns:#{namespace}" unless namespace == 'xmlns'
      attribute = attributes.get_attribute(namespace)
      attribute.remove unless attribute.nil?
      self
    end
Removes a namespace from this node.  This only works if the namespace is
 actually declared in this node.  If no argument is passed, deletes the
 default namespace.

 Evaluates to: this element
  doc = Document.new "<a xmlns:foo='bar' xmlns='twiddle'/>"
  doc.root.delete_namespace
  puts doc     # -> <a xmlns:foo='bar'/>
  doc.root.delete_namespace 'foo'
  puts doc     # -> <a/>