from xml.etree.cElementTree import Element, ElementTree
rootEm = Element("root")
childEm1 = Element("child1")
rootEm.append(childEm1)
childEm2 = Element("child2")
rootEm.append(childEm2)
ElementTree(root).write(filename)

import SOMEXMLWRITER
_f = open(filename, "w")                   ## open file first
writer = SOMEXMLWRITER(_f)
rootEm = Element("root")                   ## add Element at that time
writer.addXMLDocument(rootEm)
childEm1 = Element("child1")
rootEm.append(childEm1)
childEm2 = Element("child2")
rootEm.append(childEm2)
_f.close()                                 ## just close file... DONE!