docstr: Callable used for the check sub-command.
  
  Placed here so user_options can view it
code: def checking_metadata(self):
      """Callable used for the check sub-command.
  
      Placed here so user_options can view it"""
      return self.metadata_check
  
imports: import os
  import sys
  from glob import glob
  from warnings import warn
  from distutils.core import Command
  from distutils import dir_util
  from distutils import file_util
  from distutils import archive_util
  from distutils.text_file import TextFile
  from distutils.filelist import FileList
  from distutils import log
  from distutils.util import convert_path
  from distutils.errors import DistutilsTemplateError, DistutilsOptionError
label_desc: Use image node_id 1 for calling the sdist obj's underlying member method code with example usage: obj.checking_metadata() and returns: self