code: def _maybe_warn_git_not_installed(cwd):
      """Prints a warning if `cwd` is part of a Git repo.
  
      Warning can be disabled by setting env `NO_WARN_GIT_MISSING` to `1`.
      """
      if os.getenv("NO_WARN_GIT_MISSING") == "1":
          return
      if _is_git_repo(cwd):
          log.warning(
              "The current project appears to use Git for version control\n"
              "but git is not available on the system path. To apply Git's source\n"
              "code rules to this run, install Git [1] or specify the Git executable\n"
              "in Guild user config [2].\n"
              "\n"
              "[1] https://git-scm.com/book/en/v2/Getting-Started-Installing-Git)\n"
              "[2] https://my.guild.ai/t/user-config-reference\n"
              "\n"
              "To disable this warning, set 'NO_WARN_GIT_MISSING=1'\n"
          )
  
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 19 for calling a global function with example usage: _maybe_warn_git_not_installed(cwd) without return types