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

Given a string s, return the length of the longest substring between two equal characters, excluding the two characters. If there is no such substring return -1.
A substring is a contiguous sequence of characters within a string.
 
Please complete the following python code precisely:
```python
class Solution:
    def maxLengthBetweenEqualCharacters(self, s: str) -> int:
```