def initialize_required_metadata(self, mail):
mail_metadata = IDocumentMetadata(mail)
date_time = datetime.fromtimestamp(
utils.get_date_header(mail.msg, 'Date'))
mail_metadata.document_date = date_time.date()
# Receipt date should be None for migrated mails
mail_metadata.receipt_date = None
mail_metadata.document_author = get_author_by_email(mail)
