code: def addcomment(self, invoice_increment_id,
              comment=None, email=False, include_comment=False):
          
          if comment is None:
              comment = ""
          return bool(
              self.call(
                  'sales_order_invoice.addComment',
                  [invoice_increment_id, comment, email, include_comment]
              )
          )
docs: Add comment to invoice or change its state
  
          :param invoice_increment_id: Invoice ID