'module' object has no attribute 'net_io_counters'

Traceback (most recent call last):
  File "/usr/lib/pymodules/python2.7/ajenti/plugins/main/main.py", line 158, in handle_message
    self.ui.dispatch_event(update['uid'], update['event'], update['params'])
  File "/usr/lib/pymodules/python2.7/ajenti/ui/__init__.py", line 72, in dispatch_event
    self.root.dispatch_event(uid, event, params)
  File "/usr/lib/pymodules/python2.7/ajenti/ui/element.py", line 382, in dispatch_event
    if child.dispatch_event(uid, event, params):
  File "/usr/lib/pymodules/python2.7/ajenti/ui/element.py", line 378, in dispatch_event
    self.event(event, params)
  File "/usr/lib/pymodules/python2.7/ajenti/ui/element.py", line 402, in event
    getattr(self, 'on_%s' % self_event)(**(params or {}))
  File "/usr/lib/pymodules/python2.7/ajenti/plugins/main/main.py", line 381, in on_switch
    child.broadcast('on_page_load')
  File "/usr/lib/pymodules/python2.7/ajenti/ui/element.py", line 356, in broadcast
    getattr(self, method)(*args, **kwargs)
  File "/usr/lib/pymodules/python2.7/ajenti/plugins/network/main.py", line 45, in on_page_load
    self.refresh()
  File "/usr/lib/pymodules/python2.7/ajenti/plugins/network/main.py", line 52, in refresh
    i.tx, i.rx = sensor.value(i.name)
  File "/usr/lib/pymodules/python2.7/ajenti/api/sensors.py", line 44, in value
    self.cache[variant] = self.measure(variant)
  File "/usr/lib/pymodules/python2.7/ajenti/plugins/network/widget.py", line 22, in measure
    v = psutil.net_io_counters(pernic=True)[device]
AttributeError: 'module' object has no attribute 'net_io_counters'