# init opens up the files and does a few checks on them
def init(sample, common):

    try:
        with(common, 'r') as f:
            common_words = f.read()
            common_words = list(common_words)
            f.close()
    # convert list to lowercase
            common_words = [item.lower() for item in common_words]
            temp = []
            for word in common_words:
               word = word.replace('\n', '')
               temp += [word]
            common_words = temp
    except OSError as error:
        print('Cannot open {0:s}'.format(filename))
        raise error