def describe_resource_groups(resourceGroupArns=None):
    """
    Describes the resource groups that are specified by the ARNs of the resource groups.
    See also: AWS API Documentation
    
    Examples
    Describes the resource groups that are specified by the ARNs of the resource groups.
    Expected Output:
    
    :example: response = client.describe_resource_groups(
        resourceGroupArns=[
            'string',
        ]
    )
    
    
    :type resourceGroupArns: list
    :param resourceGroupArns: [REQUIRED]
            The ARN that specifies the resource group that you want to describe.
            (string) --
            

    :rtype: dict
    :return: {
        'resourceGroups': [
            {
                'arn': 'string',
                'tags': [
                    {
                        'key': 'string',
                        'value': 'string'
                    },
                ],
                'createdAt': datetime(2015, 1, 1)
            },
        ],
        'failedItems': {
            'string': {
                'failureCode': 'INVALID_ARN'|'DUPLICATE_ARN'|'ITEM_DOES_NOT_EXIST'|'ACCESS_DENIED'|'LIMIT_EXCEEDED'|'INTERNAL_ERROR',
                'retryable': True|False
            }
        }
    }
    
    
    """
    pass
