code: def mock_debian(tmpdir):
      """A fake Debian multi-install system"""
      tmpdir.ensure(
          f"share/gdal/{gdal_version.major}.{gdal_version.minor}/header.dxf"
      )
      tmpdir.ensure("share/proj/epsg")
      return tmpdir
  
imports: from unittest import mock
  import pytest
  from fiona._env import GDALDataFinder, PROJDataFinder
  from .conftest import gdal_version
label_desc: Use image node_id 3 for calling a global function with example usage: mock_debian(tmpdir) and returns: tmpdir