code: def selection_range(self):
          
          editor = self._editor
          doc = editor.document()
          start = doc.findBlock(
              editor.textCursor().selectionStart()).blockNumber()
          end = doc.findBlock(
              editor.textCursor().selectionEnd()).blockNumber()
          text_cursor = QTextCursor(editor.textCursor())
          text_cursor.setPosition(editor.textCursor().selectionEnd())
          if text_cursor.columnNumber() == 0 and start != end:
              end -= 1
          return start, end
docs: Returns the selected lines boundaries (start line, end line)
  
          :return: tuple(int, int)