docs: def flush_main(self):
          """Flushes the implicit main function if there is no main
          function defined."""
  
          if self.has_main:
              return
  
          self.in_main = True
  
          self.write('task main()')
          self.INDENT()
  
          if self.debug:
              print 'Flushing main:', self.fv.main
          for node in self.fv.main:
              self.v(node)
              self.NEWLINE()
  
          self.DEDENT()
  
          self.in_main = False