| This is abstract class that serves as parent for specialized writters - CDML, SVG ...
  construct_dom_tree method is virtual and should be overriden 
        
            | Methods |  |  
        | __init__ construct_dom_tree
 get_nicely_formated_document
 write_xml_to_file
 
 |  
            |  | __init__ |  
        | 
__init__ ( self,  paper )
 |  
            |  | construct_dom_tree |  
        | 
construct_dom_tree ( self,  top_levels )
 |  
            |  | get_nicely_formated_document |  
        | 
get_nicely_formated_document ( self )
 returns text form of self.document indented with dom_extensions.safe_indent |  
            |  | write_xml_to_file |  
        | 
write_xml_to_file ( self,  file )
 writes XML representation of entire papertofile |  |