def _validate_attribute_values_are_ddb_items(instance, attribute, value):
    """Validate that dictionary values in ``value`` match the structure of DynamoDB JSON
    items.

    .. note::

        We are not trying to validate the full structure of the item with this validator.
        This is just meant to verify that the values roughly match the correct format.
    """
    for data in value.values():
        if len(list(data.values())) != 1:
            raise TypeError('"{}" values do not look like DynamoDB items'.
                format(attribute.name))
