code: def test_get_forward_backward_func():
      Utils.initialize_model_parallel(
          tensor_model_parallel_size=2, pipeline_model_parallel_size=1
      )
      assert (
          schedule.get_forward_backward_func()
          == schedule.forward_backward_no_pipelining
      )
      Utils.destroy_model_parallel()
      Utils.initialize_model_parallel(
          tensor_model_parallel_size=2, pipeline_model_parallel_size=4
      )
      assert (
          schedule.get_forward_backward_func()
          == schedule.forward_backward_pipelining_without_interleaving
      )
      Utils.destroy_model_parallel()
      Utils.initialize_model_parallel(
          tensor_model_parallel_size=2,
          pipeline_model_parallel_size=4,
          virtual_pipeline_model_parallel_size=2,
      )
      assert (
          schedule.get_forward_backward_func()
          == schedule.forward_backward_pipelining_with_interleaving
      )
      Utils.destroy_model_parallel()
  
file_path: megatron-lm/tests/unit_tests/pipeline_parallel/test_schedules.py
imports: import torch
  from tests.unit_tests.test_utilities import Utils
  from megatron.core import ModelParallelConfig
  import megatron.core.pipeline_parallel.schedules
  from pytest_mock import mocker
  import pytest
label_desc: Use image node_id 1 for calling a global function with example usage: test_get_forward_backward_func() without return types