Question

I want to call a function with reactor.callLater by passing all the variables by keyword and none by index.

reactor.callLater(0, some_function, kw={'foo':'bar'})

This gives an error because kw is not expected

...
File "C:\App\Python27\lib\site-packages\twisted\internet\base.py", line 800, in runUntilCurrent
    call.func(*call.args, **call.kw)
exceptions.TypeError: function_result() got an unexpected keyword argument 'kw'

These are the docs:
http://twistedmatrix.com/documents/8.1.0/api/twisted.internet.interfaces.IReactorTime.html#callLater

What can I do about it?

Answer 1

reactor.callLater(0, some_function, foo="bar")

When a function signature say **kw they mean to just pass them as key value arguments (named). What you pass here should be exactly what you would pass if you were calling the function directly.