Challenge: Lemmatization with POS Tagging

Your are given some text in text variable. Your task is to perform a lemmatization with pos tags on this text. To do this:

1. Convert text to lowercase and save in text_lower.
2. Tokenize the text_lower string and save the result in tokens.
3. Load English stop words, convert them to set, and save in stop_words.
4. Filter out the stop words using list comprehension and save the result in filtered_tokens.
5. Perform POS tagging using the respective function and save the result in tagged_tokens.
6. Create a WordNet Lemmatizer and save it in lemmatizer.
7. Lemmatize the tokens taking their POS tags into account using list comprehension and save the result in lemmatized_tokens.