Given a collection of documents, conduct text preprocessing including tokenization, stop words removal, stemming, tf$-$idf calculation, and pairwise cosine similarity calculation using NLTK$.$ The following steps should be completed:

Install Python and NLTK $(3$ points$)$ As long as you can proceed task $2,3,$ and $4,$ you don't have to show the installation step.

Tokenize the documents into words, remove stop words, and conduct stemming $(5$ points$)$

Calculate tf$-$idf for each word in each document and generate document$-$word matrix $($each element in the matrix is the tf$-$idf score for a word in a document$)(7$ points$)$

Calculate pairwise cosine similarity for the documents $(5$ points$)$

Please include your screen shots for each of the above steps and also the final results of the pairwise cosine similarity scores in your report.