code: def resolve_rev(scm: Union["Git", "NoSCM"], rev: str) -> str:
      from scmrepo.exceptions import RevError as InternalRevError
  
      from dvc.repo.experiments.utils import fix_exp_head
  
      try:
          return scm.resolve_rev(fix_exp_head(scm, rev))
      except InternalRevError as exc:
          assert isinstance(scm, Git)
          # `scm` will only resolve git branch and tag names,
          # if rev is not a sha it may be an abbreviated experiment name
          if not (rev == "HEAD" or rev.startswith("refs/")):
              from dvc.repo.experiments.utils import (
                  AmbiguousExpRefInfo,
                  resolve_name,
              )
  
              try:
                  ref_infos = resolve_name(scm, rev).get(rev)
              except AmbiguousExpRefInfo:
                  raise RevError(
                      f"ambiguous Git revision '{rev}'"
                  )  # noqa: B904
              if ref_infos:
                  return scm.get_ref(str(ref_infos))
  
          raise RevError(str(exc))
  
imports: import os
  from contextlib import contextmanager
  from functools import partial
  from typing import TYPE_CHECKING, Iterator, List, Literal, Mapping, Optional, Union, overload
  from funcy import group_by
  from scmrepo.base import Base
  from scmrepo.git import Git
  from scmrepo.noscm import NoSCM
  from dvc.exceptions import DvcException
  from dvc.progress import Tqdm
label_desc: Use image node_id 7 for calling a global function with example usage: resolve_rev(scm, rev) and returns: scm, scm