def is_written_by(author_first_name, author_last_name, paper):
    """
    Judge whether the scraped paper belongs to the given author or not. 
    :param author_first_name:     string. First name of the author.
    :param author_last_name:    string. Last name of the author.
    :param paper:   string. arXiv papers scraped online.
    """
    if (paper.find(author_first_name) >= 0 and paper.find(author_last_name) >= 0) and len(paper) > 0:
        return True
    else:
        return False