code: def _get_preprocessor(tool):
      if tool is True:
          tool = _get_default_compiler()
      preprocess = _COMPILERS.get(tool)
      if preprocess is None:
          raise ValueError(f"unsupported tool {tool}")
      return preprocess
  
imports: import contextlib
  import logging
  import os
  import os.path
  import platform
  import re
  import sys
  from c_common.fsutil import match_glob
  from c_common.tables import parse_table
  from ..source import resolve, good_file
  from .None import errors
  from .None import pure, gcc
  from .errors import PreprocessorError, PreprocessorFailure, ErrorDirectiveError, MissingDependenciesError, OSMismatchError
  from .common import FileInfo, SourceLine
label_desc: Use image node_id 11 for calling a global function with example usage: _get_preprocessor(tool) and returns: preprocess