docs: def write(self, fd=sys.stdout):
          '''write out to file descriptor, 
          should not need to override.
          '''
          print >>fd, self.header.getvalue()
          print >>fd, self.imports.getvalue()
          
          print >>fd, '# Messages ',
          for m in self.messages:
              print >>fd, m
          
          print >>fd, ''
          print >>fd, ''
          print >>fd, '# Service Skeletons'
          for k,v in self._services.items():
              print >>fd, v.classdef.getvalue()
              print >>fd, v.initdef.getvalue()
              for s in v.methods:
                  print >>fd, s.getvalue()