'Ensures that, if present, the author property is no longer than
128 characters.'

def validate_author(self, manifest_json):

    if ('author' in manifest_json):
        author = manifest_json['author']
        if (not isinstance(author, basestring)):
            self.error('AUTHOR_NOT_STRING')
        if (len(author.strip()) < 1):
            self.error('AUTHOR_TOO_SHORT')
        if (len(author) > 128):
            self.error('AUTHOR_TOO_LONG')
