Hi, what does this mean? Specifically, why is there a colon in the second and third parameter, and why is there an an arrow at the end? Thanks

```
class Solution:
def twoSum(self, nums: List[int], target: int) -> List[int]:
```

Here is a link to the problem: https://leetcode.com/problems/two-sum/

python 3.6 introduced type hinting, which mean we could hinting the type of variable, this was done by doing `variable: type`

. (or `parameter: type`

), so for example `target`

is a parameter, of type integer.

the arrow (`->`

) allows us to type hint the return type, which is a list containing integers.

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So in the case of this example, is `List[int]`

indicative of a `list`

type?

yes, a list type, but filled with integers.

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