In [9]: q.itemActivated
Out[9]: <bound signal itemActivated of QListWidget object at 0x1d13560>
You are not calling it.
But let's try to call it.
In [10]: q.itemActivated()
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
<ipython-input-10-3602f33f377a> in <module>()
----> 1 q.itemActivated()
TypeError: native Qt signal is not callable
You can't call it, you must call the bound procedure directly. To emit a signal you must use emit.
q.itemActivated.emit(None)