*emphasized text*I want to append two lists together if the difference between the values in the new appended list will be 1. For example, if my second list is [8, 7, 6] then I would add it to my first list while removing all the numbers from the second list.

```
num = [10, 9]
current_nums = [8, 7, 6]
#after appending
num = [10, 9, 8, 7, 6] 
current_nums = #empty

```

Here is what I have tried so far:

```
def add(self, num):
    if len(self.current_nums) > 0:
        num.append(self.current_nums)
        difference = []
        for i in range(1, len(self.num)):
            difference.append(self.num[i] - self.num[i-1])

        res = difference.count(difference[0]) == len(difference)
        if res == True:
            self.current_nums.pop()           

```

When I try to append the first list to the second list I get an AttributeError: type object 'Board' has no attribute 'append'. How can I append a list to a class object?