code: def test_seg_calctopncc():
      """Test interfaces for seg_CalctoNCC"""
      # Create a node object
      calctopncc = CalcTopNCC()
  
      # Check if the command is properly defined
      cmd = get_custom_path("seg_CalcTopNCC", env_dir="NIFTYSEGDIR")
      assert calctopncc.cmd == cmd
  
      # test raising error with mandatory args absent
      with pytest.raises(ValueError):
          calctopncc.run()
  
      # Assign some input data
      in_file = example_data("im1.nii")
      file1 = example_data("im2.nii")
      file2 = example_data("im3.nii")
      calctopncc.inputs.in_file = in_file
      calctopncc.inputs.num_templates = 2
      calctopncc.inputs.in_templates = [file1, file2]
      calctopncc.inputs.top_templates = 1
  
      cmd_tmp = (
          "{cmd} -target {in_file} -templates 2 {file1} {file2} -n 1"
      )
      expected_cmd = cmd_tmp.format(
          cmd=cmd, in_file=in_file, file1=file1, file2=file2
      )
  
      assert calctopncc.cmdline == expected_cmd
  
imports: import pytest
  from ....testing import example_data
  from ...niftyreg import get_custom_path
  from ...niftyreg.tests.test_regutils import no_nifty_tool
  from ..None import LabelFusion, CalcTopNCC
label_desc: Use image node_id 2 for calling a global function with example usage: test_seg_calctopncc() without return types