Describe the default_namespace parameter of ElemetTree.write.

Doc/library/xml.etree.elementtree.rst

@@ -468,16 +468,18 @@ ElementTree Objects
       root element.
 
 
-   .. method:: write(file, encoding="us-ascii", xml_declaration=None, method="xml")
+   .. method:: write(file, encoding="us-ascii", xml_declaration=None, \
+                     default_namespace=None, method="xml")
 
       Writes the element tree to a file, as XML.  *file* is a file name, or a
-      :term:`file object` opened for writing.  *encoding* [1]_ is the output encoding
-      (default is US-ASCII).  Use ``encoding="unicode"`` to write a Unicode string.
-      *xml_declaration* controls if an XML declaration
+      :term:`file object` opened for writing.  *encoding* [1]_ is the output
+      encoding (default is US-ASCII).  Use ``encoding="unicode"`` to write a
+      Unicode string.  *xml_declaration* controls if an XML declaration
       should be added to the file.  Use False for never, True for always, None
-      for only if not US-ASCII or UTF-8 or Unicode (default is None).  *method* is
-      either ``"xml"``, ``"html"`` or ``"text"`` (default is ``"xml"``).
-      Returns an (optionally) encoded string.
+      for only if not US-ASCII or UTF-8 or Unicode (default is None).
+      *default_namespace* sets the default XML namespace (for "xmlns").
+      *method* is either ``"xml"``, ``"html"`` or ``"text"`` (default is
+      ``"xml"``).  Returns an (optionally) encoded string.
 
 This is the XML file that is going to be manipulated::
 

Lib/xml/etree/ElementTree.py

@@ -802,11 +802,12 @@ class ElementTree:
     # @param **options Options, given as keyword arguments.
     # @keyparam encoding Optional output encoding (default is US-ASCII).
     #     Use "unicode" to return a Unicode string.
-    # @keyparam method Optional output method ("xml", "html", "text" or
-    #     "c14n"; default is "xml").
     # @keyparam xml_declaration Controls if an XML declaration should
     #     be added to the file.  Use False for never, True for always,
     #     None for only if not US-ASCII or UTF-8 or Unicode.  None is default.
+    # @keyparam default_namespace Sets the default XML namespace (for "xmlns").
+    # @keyparam method Optional output method ("xml", "html", "text" or
+    #     "c14n"; default is "xml").
 
     def write(self, file_or_filename,
               # keyword arguments