```
def dominantIndex(self, nums):
return nums.index(max(nums)) if all(max(nums) >= num * 2 for num in nums if num != max(nums)) else -1
```

Clearer version:

```
def dominantIndex(self, nums):
max_ele = max(nums)
for num in nums:
if num != max_ele and max_ele < num * 2:
return -1
return nums.index(max_ele)
```