code: def test_backspace(_buffer):
      _buffer.insert_text("some_text")
      _buffer.cursor_left()
      _buffer.cursor_left()
      _buffer.delete_before_cursor()
  
      assert _buffer.text == "some_txt"
      assert _buffer.cursor_position == len("some_t")
  
file_path: catboost/contrib/python/prompt-toolkit/py3/tests/test_buffer.py
imports: from __future__ import annotations
  import pytest
  from prompt_toolkit.buffer import Buffer
label_desc: Use image node_id 5 for calling a global function with example usage: test_backspace(_buffer) without return types