code: public static void validateConfiguration(Configuration conf) throws IOException {
      // Ensure the BigQuery output information is valid.
      ConfigurationUtil.getMandatoryConfig(conf, REQUIRED_KEYS);
  
      // Run through the individual getters as they manage error handling.
      getProjectId(conf);
      getTableSchema(conf);
      getFileFormat(conf);
      getFileOutputFormat(conf);
      getGcsOutputPath(conf);
    }
docs: Helper function that validates the output configuration. Ensures the project id, dataset id,
  and table id exist in the configuration. This also ensures that if a schema is provided, that
  it is properly formatted.
  
  @param conf the configuration to validate.
  @throws IOException if the configuration is missing a key, or there's an issue while parsing
  the schema in the configuration.