docstr: Provide backwards compatibility for old pipelines
  
  setting_values - the strings to be fed to settings
  variable_revision_number - the version number at time of saving
  module_name - name of original module
docstr_tok: ["Provide","backwards","compatibility","for","old","pipelines","setting_values","-","the","strings","to","be","fed","to","settings","variable_revision_number","-","the","version","number","at","time","of","saving","module_name","-","name","of","original","module"]
code: def upgrade_settings(
      self, setting_values, variable_revision_number, module_name
  ):
      """Provide backwards compatibility for old pipelines
  
      setting_values - the strings to be fed to settings
      variable_revision_number - the version number at time of saving
      module_name - name of original module
      """
      if variable_revision_number == 1:
          #
          # Added hole size questions
          #
          setting_values = setting_values + ["Yes", "10"]
          variable_revision_number = 2
      if variable_revision_number == 2:
          #
          # Added graph stuff
          #
          setting_values = setting_values + [
              "No",
              "None",
              Directory.static_join_string(
                  DEFAULT_OUTPUT_FOLDER_NAME, "None"
              ),
              "None",
              "None",
          ]
          variable_revision_number = 3
      return setting_values, variable_revision_number
  
imports: import os
  import centrosome.cpmorphology
  import centrosome.propagate
  import numpy
  import scipy.ndimage
  from cellprofiler_core.constants.measurement import COLTYPE_FLOAT
  from cellprofiler_core.constants.measurement import COLTYPE_INTEGER
  from cellprofiler_core.image import Image
  from cellprofiler_core.measurement import Measurements
  from cellprofiler_core.module import Module
  from cellprofiler_core.preferences import ABSOLUTE_FOLDER_NAME
  from cellprofiler_core.preferences import DEFAULT_INPUT_FOLDER_NAME
  from cellprofiler_core.preferences import DEFAULT_INPUT_SUBFOLDER_NAME
  from cellprofiler_core.preferences import DEFAULT_OUTPUT_FOLDER_NAME
  from cellprofiler_core.preferences import DEFAULT_OUTPUT_SUBFOLDER_NAME
  from cellprofiler_core.preferences import get_default_colormap
  from cellprofiler_core.setting import Binary
  from cellprofiler_core.setting.subscriber import LabelSubscriber, ImageSubscriber
  from cellprofiler_core.setting.text import ImageName, Directory
  from cellprofiler_core.setting.text import Integer
  from cellprofiler_core.setting.text import Text
  from cellprofiler_core.utilities.core.object import size_similarly
  from centrosome.cpmorphology import fixup_scipy_ndimage_result
  from scipy.ndimage import grey_dilation, grey_erosion
label_desc: Use image node_id 13 for calling the MeasureObjectSkeleton obj's underlying member method code with example usage: obj.upgrade_settings(setting_values, variable_revision_number, module_name) and returns: setting_values,  variable_revision_number