code: def _try_git_source_iter(dir):
      """Class that conforms to the util.try_apply scheme for iterating source.
  
      Raises `util.TryFailed` if git does not provide a list of files.
      """
      tracked = _try_git_ls_files(dir, untracked=False)
      untracked = _try_git_ls_files(dir, untracked=True)
      return tracked + untracked
  
imports: import collections
  import logging
  import re
  import os
  import subprocess
  from guild import config
  from guild import file_util
  from guild import util
  from guild.file_util import FileSelectRule
label_desc: Use image node_id 7 for calling a global function with example usage: _try_git_source_iter(dir) and returns: unknown