def flatten(x): if isinstance(x, list): return [a for i in x for a in flatten(i)] else: return [x]
Here is what the above code is Doing:
1. If x is a list, iterate over it and recursively call flatten on each element.
2. If x is not a list, return a list with x as its only element.
3. In the end, we use a list comprehension to concatenate all the lists together.