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

The DNA sequence is composed of a series of nucleotides abbreviated as 'A', 'C', 'G', and 'T'.

For example, "ACGAATTCCG" is a DNA sequence.

When studying DNA, it is useful to identify repeated sequences within the DNA.
Given a string s that represents a DNA sequence, return all the 10-letter-long sequences (substrings) that occur more than once in a DNA molecule. You may return the answer in any order.
 
Please complete the following python code precisely:
```python
class Solution:
    def findRepeatedDnaSequences(self, s: str) -> List[str]:
```