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

There are n servers numbered from 0 to n - 1 connected by undirected server-to-server connections forming a network where connections[i] = [ai, bi] represents a connection between servers ai and bi. Any server can reach other servers directly or indirectly through the network.
A critical connection is a connection that, if removed, will make some servers unable to reach some other server.
Return all critical connections in the network in any order.
 
Please complete the following python code precisely:
```python
class Solution:
    def criticalConnections(self, n: int, connections: List[List[int]]) -> List[List[int]]:
```