Return the substitutions for the templating replacements.

def substitutes(self):
        """ Return the substitutions for the templating replacements. """
        author_collector = AuthorCollector()
        mail_collector = AuthorMailCollector()
        substitute_dict = {
            'project': self.project_name,
            'project_lower': self.project_name.lower(),
            'date': date.today().isoformat(),
            'author': author_collector.collect(),
            'author_email': mail_collector.collect(),
        }
        return substitute_dict