def METHOD_NAME(entries, unused_options_map):
    """Verify that the document entries point to existing files.
    Args:
      entries: a list of directives whose documents need to be validated.
      unused_options_map: A parser options dict. We're not using it.
    Returns:
      The same list of entries, and a list of new errors, if any were encountered.
    """
    errors = []
    for entry in entries:
        if not isinstance(entry, data.Document):
            continue
        if not path.exists(entry.filename):
            errors.append(
                DocumentError(entry.meta,
                              'File does not exist: "{}"'.format(entry.filename),
                              entry))
    return entries, errors