code: def mock_shell():
      with mock.patch("wandb.docker.shell") as mock_shell:
          mock_shell.return_value = None
          yield mock_shell
  
imports: import platform
  from unittest import mock
  import pytest
  from wandb.docker import is_buildx_installed, should_add_load_argument
label_desc: Use image node_id 1 for calling a global function with example usage: mock_shell() without return types