code: def dump(self,filename=None):
          
  
          if filename is None:
              with io.BytesIO() as buffer:
                  self.dump(filename=buffer)
                  bytes = buffer.getvalue()
                  getattr(sys.stdout, 'buffer', sys.stdout).write(bytes)
          else:
              self.tree.write(filename,encoding='UTF-8',pretty_print=True,xml_declaration=True)
docs: Dumps the object to an output filename (or open file descriptor). The filename
          parameter is optional, and if it is not provided, the standard output will be used
          @type filename: string or file descriptor
          @param filename: file where to dump the object (default standard output)