code: function toKeyValueStrings(dynamoDBMap) {
    return dynamoDBMap && typeof dynamoDBMap === 'object' ?
      Object.getOwnPropertyNames(dynamoDBMap).map(key => `${key}:${stringify(toValueFromAttributeValue(dynamoDBMap[key]))}`) : [];
  }
docs: Extracts an array of colon-separated key name and value strings from the given DynamoDB map object.
  @param {Object} dynamoDBMap - a DynamoDB map object
  @returns {string[]} an array of colon-separated key name and value strings