Please solve the programming task below using a self-contained code snippet in a markdown code block.

You are given a 0-indexed integer array stations of length n, where stations[i] represents the number of power stations in the ith city.
Each power station can provide power to every city in a fixed range. In other words, if the range is denoted by r, then a power station at city i can provide power to all cities j such that |i - j| <= r and 0 <= i, j <= n - 1.

Note that |x| denotes absolute value. For example, |7 - 5| = 2 and |3 - 10| = 7.

The power of a city is the total number of power stations it is being provided power from.
The government has sanctioned building k more power stations, each of which can be built in any city, and have the same range as the pre-existing ones.
Given the two integers r and k, return the maximum possible minimum power of a city, if the additional power stations are built optimally.
Note that you can build the k power stations in multiple cities.
 
Please complete the following python code precisely:
```python
class Solution:
    def maxPower(self, stations: List[int], r: int, k: int) -> int:
```