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

Given an array of strings words representing an English Dictionary, return the longest word in words that can be built one character at a time by other words in words.
If there is more than one possible answer, return the longest word with the smallest lexicographical order. If there is no answer, return the empty string.
Note that the word should be built from left to right with each additional character being added to the end of a previous word. 
 
Please complete the following python code precisely:
```python
class Solution:
    def longestWord(self, words: List[str]) -> str:
```