import re


def process_data(file_name):
    """
    Input: 
        A file_name which is found in your current directory. You just have to read it in. 
    Output: 
        words: a list containing all the words in the corpus (text file you read) in lower case. 
    """
    words = [] # return this variable correctly
    
    with open(file_name) as f:
        for line in f:
            words.extend(re.findall(r'\w+', line.lower()))            
    
    return words