'Ensures that, if present, the description property is no longer than
132 characters.
https://developer.chrome.com/extensions/manifest/description'

def validate_description(self, manifest_json):

    if ('description' in manifest_json):
        description = manifest_json['description']
        if (not isinstance(description, basestring)):
            self.error('DESCRIPTION_NOT_STRING')
        if (len(description.strip()) > 132):
            self.error('DESCRIPTION_TOO_LONG')
