code: function updateExpressionAttributeNames(opts, expressionAttributeNames) {
    if (!expressionAttributeNames || typeof expressionAttributeNames !== 'object') return opts;
    if (!opts) opts = {};
    if (!opts.ExpressionAttributeNames) opts.ExpressionAttributeNames = {};
  
    const keys = Object.getOwnPropertyNames(expressionAttributeNames);
    keys.forEach(key => {
      opts.ExpressionAttributeNames[key] = expressionAttributeNames[key];
    });
  
    return opts;
  }
docs: Updates the ExpressionAttributeNames map of the given opts with the given map of extra expression attribute names.
  @param {DynamoGetOpts|DynamoQueryOpts|Object|undefined} opts - the options to update
  @param {Object.<string, string>} expressionAttributeNames - the map of extra expression attribute names to add
  @return {DynamoGetOpts|DynamoQueryOpts|Object} the updated options