code: def drop_img_part():
      def f(img, part_name="right_hemisphere"):
          mesh = img.mesh.copy()
          mesh.pop(part_name)
          data = img.data.copy()
          data.pop(part_name)
          return SurfaceImage(mesh, data)
  
      return f
  
file_path: nilearn/nilearn/experimental/surface/tests/conftest.py
imports: from typing import Callable
  import numpy
  import pytest
  from nilearn.experimental.surface import InMemoryMesh, PolyMesh, SurfaceImage, load_fsaverage
label_desc: Use image node_id 9 for calling a global function with example usage: drop_img_part() and returns: f, SurfaceImage