Use __slots__ throughout instead of __dict__, to reduce the memory usage.

Lib/xml/dom/expatbuilder.py

@@ -283,27 +283,23 @@ class ExpatBuilder:
         elif childNodes and childNodes[-1].nodeType == TEXT_NODE:
             node = childNodes[-1]
             value = node.data + data
-            d = node.__dict__
-            d['data'] = d['nodeValue'] = value
+            node.data = value
             return
         else:
             node = minidom.Text()
-            d = node.__dict__
-            d['data'] = d['nodeValue'] = data
-            d['ownerDocument'] = self.document
+            node.data = data
+            node.ownerDocument = self.document
         _append_child(self.curNode, node)
 
     def character_data_handler(self, data):
         childNodes = self.curNode.childNodes
         if childNodes and childNodes[-1].nodeType == TEXT_NODE:
             node = childNodes[-1]
-            d = node.__dict__
-            d['data'] = d['nodeValue'] = node.data + data
+            node.data = node.data + data
             return
         node = minidom.Text()
-        d = node.__dict__
-        d['data'] = d['nodeValue'] = node.data + data
-        d['ownerDocument'] = self.document
+        node.data = node.data + data
+        node.ownerDocument = self.document
         _append_child(self.curNode, node)
 
     def entity_decl_handler(self, entityName, is_parameter_entity, value,
@@ -363,11 +359,8 @@ class ExpatBuilder:
                 a = minidom.Attr(attributes[i], EMPTY_NAMESPACE,
                                  None, EMPTY_PREFIX)
                 value = attributes[i+1]
-                d = a.childNodes[0].__dict__
-                d['data'] = d['nodeValue'] = value
-                d = a.__dict__
-                d['value'] = d['nodeValue'] = value
-                d['ownerDocument'] = self.document
+                a.value = value
+                a.ownerDocument = self.document
                 _set_attribute_node(node, a)
 
         if node is not self.document.documentElement:
@@ -761,11 +754,8 @@ class Namespaces:
                 else:
                     a = minidom.Attr("xmlns", XMLNS_NAMESPACE,
                                      "xmlns", EMPTY_PREFIX)
-                d = a.childNodes[0].__dict__
-                d['data'] = d['nodeValue'] = uri
-                d = a.__dict__
-                d['value'] = d['nodeValue'] = uri
-                d['ownerDocument'] = self.document
+                a.value = uri
+                a.ownerDocuemnt = self.document
                 _set_attribute_node(node, a)
             del self._ns_ordered_prefixes[:]
 
@@ -785,12 +775,9 @@ class Namespaces:
                                      aname, EMPTY_PREFIX)
                     _attrs[aname] = a
                     _attrsNS[(EMPTY_NAMESPACE, aname)] = a
-                d = a.childNodes[0].__dict__
-                d['data'] = d['nodeValue'] = value
-                d = a.__dict__
-                d['ownerDocument'] = self.document
-                d['value'] = d['nodeValue'] = value
-                d['ownerElement'] = node
+                a.ownerDocument = self.document
+                a.value = value
+                a.ownerElement = node
 
     if __debug__:
         # This only adds some asserts to the original