description: Optional[str] = None
    url: AnyUrl


class Schema(BaseModelWithConfig):
    # Ref: JSON Schema 2020-12: https://json-schema.org/draft/2020-12/json-schema-core.html#name-the-json-schema-core-vocabu
    # Core Vocabulary
    schema_: Optional[str] = Field(default=None, alias="$schema")
    vocabulary: Optional[str] = Field(default=None, alias="$vocabulary")
    id: Optional[str] = Field(default=None, alias="$id")

    # Make sure that the desired input key and output key is present.
    self.assertIn('input_vocabs', inputs.keys())
    self.assertIn('lookup', outputs.keys())

    # Representative dataset is composed of a set of vocabs for table lookup.
    repr_ds = [
        {'input_vocabs': np.array([b'hello', b'model', b'quantization'])}
        for _ in range(4)
    ]

    signature_def_keys = [signature_def_key]