# gdtest_type_aliases > A synthetic test package built from PEP 695 type aliases ## Docs ### API Reference #### Classes > Main classes provided by the package - [Ledger](reference/Ledger.html): An append-only record of contract state changes #### Functions > Utility functions - [sign](reference/sign.html): Sign a contract with the named scheme - [summarize](reference/summarize.html): Group contracts by name for one jurisdiction #### Constants > Module-level constants and data - [Signature](reference/Signature.html) #### Type Aliases > Type alias definitions - [Clause](reference/Clause.html): Type alias - [ContractId](reference/ContractId.html): Type alias - [Jurisdiction](reference/Jurisdiction.html): Type alias - [Key](reference/Key.html): Type alias - [Named](reference/Named.html): Type alias - [Pair](reference/Pair.html): Type alias - [Row](reference/Row.html): Type alias - [Validator](reference/Validator.html): Type alias