When calling a function, number of arguments inside parentheses must match the number of arguments in function definition.
So if you have empty parentheses in your function definition like this:
func interact():
then you must call it with no arguments as well, like this:
x.interact()
Because this function expects zero arguments.
By contrast, if you define a function to expect one argument like this:
func interact(something):
Then you must supply that one argument when calling it, like this:
x.interact(anything)
Same holds true for any number of function arguments.
