code: def read_file(filepath):
      
  
      with _FILE_CACHE_LOCK:
          if filepath not in _FILE_CACHE:
              _FILE_CACHE[filepath] = _read_file(filepath)
      return _FILE_CACHE[filepath]
docs: Retrieves the contents of the specified file.
  
      This function performs simple caching so that the same file isn't read more
      than once per process.
  
      :param filepath: the file to read
      :type filepath: str
      :returns: str