code: function unwrap1(dynamoData) {
    var keys = Object.keys(dynamoData);
    if (keys.length !== 1)
      throw new Error('Unexpected DynamoDB AttributeValue');
    var typeStr = keys[0];
    if (!unwrapFns.hasOwnProperty(typeStr))
      throw errs.NoDatatype;
    var val = dynamoData[typeStr];
    return unwrapFns[typeStr] ? unwrapFns[typeStr](val) : val;
  }
docs: Unwrap a single DynamoDB's AttributeValue to a value of the appropriate
  javascript type.
  @param {Object} attributeValue The DynamoDB AttributeValue.
  @return {String|Number|Array}  The javascript value.