diff --git a/src/nlp.py b/src/nlp.py
index 70c1e8d..c11c951 100644
--- a/src/nlp.py
+++ b/src/nlp.py
@@ -14,13 +14,10 @@ class NLP:
         tokens = [token.lemma_ for token in doc]
         return ' '.join(tokens)
 
-    def _get_nouns(self, tree: ParseTreeNode) -> List[str]:
+    def get_nouns(self, tree: ParseTree) -> List[str]:
         nouns: List[ParseTreeNode] = []
-        for node in LevelOrderIter(tree):
+        for node in LevelOrderIter(tree.get_tree_root()):
             if node.upos != 'NOUN':
                 continue
             nouns.append(node)
-        return [self._lemmatizer(noun.lemma) for noun in nouns]
-
-    def get_nouns(self, tree: ParseTree) -> List[str]:
-        return self._get_nouns(tree.get_tree_root())
+        return list(set([self.lemmatizer(noun.lemma) for noun in nouns]))