Adventures with Trie data structure

adventuresWithTries.py

class Node():
    def __init__(self, character):
        self.letter = character
        self.isEndOfWord = False
        self.children = {}

class Trie:
    def __init__(self):
        """
        Initialize an empty Node as root.
        """
        self.root = Node("")  
        
    def _getIndex(self, character):
        return ord(character) - ord("a")    

    def insert(self, word):
        """
        Inserts a word into the trie.
        """
        cur = self.root
        for letter in word:
            idx = self._getIndex(letter)
            if not cur.children.get(idx):
                cur.children[idx] = Node(letter)
            cur = cur.children[idx]
        cur.isEndOfWord = True
         
    def search(self, word):
        """
        Returns if the word is in the trie.
        """
        cur = self.root
        for letter in word:
            idx = self._getIndex(letter)
            if not cur.children.get(idx):
                return False
            cur = cur.children[idx]
        return cur and cur.isEndOfWord        

    def startsWith(self, prefix):
        """
        Returns if there is any word in the trie that starts with the given prefix.
        """
        cur = self.root
        for letter in prefix:
            idx = self._getIndex(letter)
            if not cur.children.get(idx):
                return False
            cur = cur.children[idx]
        return True


    def delete(self, word):
        """
        Returns if there is any word in the trie that starts with the given prefix.
        """
        cur = self.root
        for letter in word[:-1]:
            idx = self._getIndex(letter)
            if not cur.children.get(idx):
                return False
            cur = cur.children[idx]
        lastIndex = self._getIndex(word[-1])
        if cur.children.get(lastIndex):
            del cur.children[lastIndex]
            return True
        return False
       

if __name__ == "__main__":
    trie = Trie()
    print(trie.insert("apple"))
    print(trie.search("apple")) 
    print(trie.search("app"))
    print(trie.startsWith("app"))
    print(trie.insert("app"))
    print(trie.search("app"))
    print(trie.delete("app"))
    print(trie.search("app"))