def METHOD_NAME(self):
    """Private method to check that `products` is a `dict` of `HASHDICTs`."""
    if not isinstance(self.products, dict):
        raise securesystemslib.exceptions.FormatError(
            "Invalid Link: field `products` must be of type dict, got: {}".format(
                type(self.products)
            )
        )
    for product in list(self.products.values()):
        securesystemslib.formats.HASHDICT_SCHEMA.check_match(product)