code: def switch(repo: "Repo", rev: str) -> Iterator[str]:
      """Switch to a specific revision."""
      from dvc.scm import resolve_rev
  
      if rev != "workspace":
          rev = resolve_rev(repo.scm, rev)
  
      repo_root_parts: Tuple[str, ...] = ()
      if repo.fs.isin(repo.root_dir, repo.scm.root_dir):
          repo_root_parts = repo.fs.relparts(
              repo.root_dir, repo.scm.root_dir
          )
  
      cwd_parts: Tuple[str, ...] = ()
      if repo.fs.isin(repo.fs.getcwd(), repo.scm.root_dir):
          cwd_parts = repo.fs.relparts(
              repo.fs.getcwd(), repo.scm.root_dir
          )
  
      saved_fs = repo.fs
      saved_root = repo.root_dir
      saved_dvc_dir = repo.dvc_dir
      try:
          _switch_fs(repo, rev, repo_root_parts, cwd_parts)
          yield rev
      finally:
          repo.fs = saved_fs
          repo.root_dir = saved_root
          repo.dvc_dir = saved_dvc_dir
          repo._reset()
  
file_path: dvc/dvc/repo/brancher.py
imports: from contextlib import contextmanager
  from typing import TYPE_CHECKING, Iterator, Optional, Tuple
  from scmrepo.git import Git
  from dvc.exceptions import NotDvcRepoError
  from dvc.log import logger
  from dvc.scm import iter_revs
label_desc: Use image node_id 3 for calling a global function with example usage: switch(repo, rev) without return types