code: def delete_line(self):
          
          cursor = self.textCursor()
          if self.has_selected_text():
              self.extend_selection_to_complete_lines()
              start_pos, end_pos = cursor.selectionStart(), cursor.selectionEnd()
              cursor.setPosition(start_pos)
          else:
              start_pos = end_pos = cursor.position()
          cursor.beginEditBlock()
          cursor.setPosition(start_pos)
          cursor.movePosition(QTextCursor.StartOfBlock)
          while cursor.position() <= end_pos:
              cursor.movePosition(QTextCursor.EndOfBlock, QTextCursor.KeepAnchor)
              if cursor.atEnd():
                  break
              cursor.movePosition(QTextCursor.NextBlock, QTextCursor.KeepAnchor)
          cursor.removeSelectedText()
          cursor.endEditBlock()
          self.ensureCursorVisible()
docs: Delete current line