As a data scientist working in the higher education field, you aim to extract useful information from an article about at$-$risk calculus students. To achieve this, you plan to perform the following tasks on the 'AIED$2021\_$at$\_$risk$\_$pred.pdf$\text{'}$ file.

$$ Q$1.$ Extract all texts from the given pdf file.

$$ Q$2.$ Use regular expression to locate any years mentioned in the document.

$$ Q$3.$ Use regular expression to identify all words that start with a capital letter, which might be useful to find key concepts.

$$ Q$4.$ Use regular expression to find specific machine learning algorithms $($e$.$g$.,$ Logistic Regression, Support Vector Machines, Random Forest$)$ mentioned in the document

$$ Q$5.$ Remove all special characters, punctuation in the document using regular expression.

$$ Q$6.$ Remove the hyperlink URL in the document using regular expression.

$$ Q$7.$ Remove all words containing at most two characters such as $"$a$","$an$","$in$","$on$","$if$"$ using regular expression.

$$ Q$8.$ Remove the following four words: "are", "but", "very", "could" using regular expression.