fix: add self to the prototype of functions

Author: qfeuilla

module04/subject/en.subject.tex

@@ -165,10 +165,10 @@ \section*{Instructions}
 % ---------------------------------- %
 Write a class named \texttt{FileLoader} which implements the following methods:  
 \begin{itemize}
-  \item \texttt{load(path)}: takes as an argument the file path of the dataset to load, 
+  \item \texttt{load(self, path)}: takes as an argument the file path of the dataset to load, 
     displays a message specifying the dimensions of the dataset (e.g. 340 x 500) 
     and returns the dataset loaded as a pandas.DataFrame.
-  \item \texttt{display(df, n)}: takes a pandas.DataFrame and an integer as arguments, 
+  \item \texttt{display(self, df, n)}: takes a pandas.DataFrame and an integer as arguments, 
     displays the first n rows of the dataset if n is positive, or the last n rows if n is negative.
 \end{itemize}