code: def trace(self, level=logging.DEBUG, show_enter=True, show_exit=True):
          
          from . import log_trace
          return log_trace(self, level, show_enter, show_exit)
docs: Functions decorated with this function show function entry and exit with
          values, defaults to debug log level.
  
          :param level: log severity to use for function tracing
          :param show_enter: log function entry
          :param show_enter: log function exit
  
          Example use:
  
          .. sourcecode:: python
  
              log = rootpy.log["/myapp"]
              @log.trace()
              def salut():
                  return
  
              @log.trace()
              def hello(what):
                  salut()
                  return "42"
  
              hello("world")
              # Result:
              #   DEBUG:myapp.trace.hello] > ('world',) {}
              #   DEBUG:myapp.trace.salut]  > () {}
              #   DEBUG:myapp.trace.salut]  < return None [0.00 sec]
              #   DEBUG:myapp.trace.hello] < return 42 [0.00 sec]
  
          Output:
  
          .. sourcecode:: none