code: def svn_mirror_url():
      """Return the URL for the SVN mirror
  
      Use the value of the environment variable, "CP_SVNMIRROR_URL" with
      a default of http://cellprofiler.org/svnmirror.
      """
      return os.environ.get(
          "CP_SVNMIRROR_URL", "http://cellprofiler.org/svnmirror"
      )
  
imports: import logging
  import base64
  import hashlib
  import numpy
  import os
  import unittest
  import tempfile
  import functools
  import scipy.io.matlab.mio
  import numpy
  import skimage.io
  from urllib.request import URLopener
  import cellprofiler_core.utilities.legacy
  from cellprofiler_core.pipeline import ImageFile
  import tests.frontend
label_desc: Use image node_id 3 for calling a global function with example usage: svn_mirror_url() and returns: os