code: def to_file(self, path, format='csv', csv_delimiter=',', csv_header=True, use_cache=True,
                dialect=None, billing_tier=None):
      
      self.results(use_cache=use_cache, dialect=dialect, billing_tier=billing_tier) \
          .to_file(path, format=format, csv_delimiter=csv_delimiter, csv_header=csv_header)
      return path
docs: Save the results to a local file in CSV format.
  
      Args:
        path: path on the local filesystem for the saved results.
        format: the format to use for the exported data; currently only 'csv' is supported.
        csv_delimiter: for CSV exports, the field delimiter to use. Defaults to ','
        csv_header: for CSV exports, whether to include an initial header line. Default true.
        use_cache: whether to use cached results or not.
        dialect : {'legacy', 'standard'}, default 'legacy'
            'legacy' : Use BigQuery's legacy SQL dialect.
            'standard' : Use BigQuery's standard SQL (beta), which is
            compliant with the SQL 2011 standard.
        billing_tier: Limits the billing tier for this job. Queries that have resource
            usage beyond this tier will fail (without incurring a charge). If unspecified, this
            will be set to your project default. This can also be used to override your
            project-wide default billing tier on a per-query basis.
      Returns:
        The path to the local file.
      Raises:
        An Exception if the operation failed.