TypeError: input() takes 2 positional arguments but 3 were given

Question

I'm trying to learn basics of python and there is this input() command in eric6 and the command and the error is this:

size  = int(input('size: '))
Traceback (innermost last):
  File "<stdin>", line 1, in <module>
  File "C:\Users\Asus\AppData\Local\Programs\Python\Python35\Lib\site-packages\eric6\DebugClients\Python\DebugClientBase.py", line 74, in DebugClientInput
    return DebugClientInstance.input(prompt, echo)
TypeError: input() takes 2 positional arguments but 3 were given