docstr: Calls `os.path.expanduser` on install_base, install_platbase and
  root.
code: def expand_basedirs(self):
      """Calls `os.path.expanduser` on install_base, install_platbase and
      root."""
      self._expand_attrs(["install_base", "install_platbase", "root"])
  
imports: import sys
  import sysconfig
  import os
  import re
  from distutils import log
  from distutils.core import Command
  from distutils.debug import DEBUG
  from distutils.sysconfig import get_config_vars
  from distutils.errors import DistutilsPlatformError
  from distutils.file_util import write_file
  from distutils.util import convert_path, subst_vars, change_root
  from distutils.util import get_platform
  from distutils.errors import DistutilsOptionError
  from site import USER_BASE
  from site import USER_SITE
label_desc: Use image node_id 8 for calling the install obj's underlying member method code with example usage: obj.expand_basedirs() without return types