code: def _find_c_source(base_path):
      file_exists = os.path.exists
      for ext in C_FILE_EXTENSIONS:
          file_name = base_path + ext
          if file_exists(file_name):
              return file_name
      return None
  
imports: from __future__ import absolute_import
  import re
  import os.path
  import sys
  from collections import defaultdict
  from coverage.plugin import CoveragePlugin, FileTracer, FileReporter
  from coverage.files import canonical_filename
  from .Utils import find_root_package_dir, is_package_dir, open_source_file
  from .None import __version__
label_desc: Use image node_id 1 for calling a global function with example usage: _find_c_source(base_path) and returns: None, file_name