code: def retrieve_files():
      
  
      all_files = []
      for location in cfg.CONF.locations or []:
          # if local path then make sure it is absolute
          if not location.startswith('\\'):
              location = os.path.abspath(os.path.expanduser(location))
  
          LOG.debug('searching [%s]', location)
          for root, _, files in os.walk(location):
              LOG.debug('found file(s) %s', files)
              for name in files:
                  filepath = os.path.join(root, name)
                  if (os.access(filepath, os.R_OK) and
                          not _is_blacklisted_filename(filepath) and
                          _is_valid_extension(os.path.splitext(name)[1])):
                      all_files.append(filepath)
  
      return all_files
docs: Get list of files found in provided locations.
  
      Search through the paths provided to find files for processing.
  
      :returns: absolute path of filename
      :rtype: list