def METHOD_NAME(self):
    """Rule 5: Use the imperative mood in the subject line.
    We can only check for common mistakes here, like using
    the -ing form of a verb or non-imperative version of
    common verbs
    """
    firstword = self.subject_words[0]
    if firstword.endswith("ing"):
        return False
    for word in self.common_first_words:
        if firstword.startswith(word) and firstword != word:
            return False
    return True