This is my very first question.
I have not programmed anything since sinclair's 48k times, and now i'm trying to learn python.

I have browsed other questions related to "None is not callable" but unfortunately I have not clarified anything.
I was trying to avoid this but... i need your help.

I am trying to understand list comprehension but when trying to do the exercise I get the following error on line 27. 'NoneType' object is not callable

```
new_node = None (d, self.root)

```

Maybe it has to do with the order in which I call the methods, but I don't see it ...
**Thanks for your attention and sorry again**.

v.

```
    class Node(object):

        def __init__(self, d, n=None):
            self.data = d
            self.next_node = n

        def get_next(self):
            return self.next_node

        def set_next(self, n):
            self.next_node = n

        def set_data(self, d):
            self.data = d

    class LinkedList(object):

        def __init__(self, r=None):
            self.root = r
            self.size = 0

        def get_size(self):
            return self.size

        def add(self, d):
            new_node = None (d, self.root)
            self.root = new_node
            self.size += 1

        def remove(self, d):
            this_node = self.root
            prev_node = None

            while this_node:
                if this_node.get_data() == d:
                    if prev_node:
                        prev_node.set_next(this_node.get_next())

                    else:
                        self.root = this_node.get_next()

                    self.size -= 1
                    return True

                else:
                    prev_node = this_node
                    this_node = this_node.get_next()

            return False

    lista = LinkedList()    
    lista.add(16)
    lista.add(23)
    lista.add(53)
    lista.remove(23)

```