3. Sign to UserOperation

Operations for account abstraction (commonly referred to as "User Operations") differ from standard operations as they include the signature of the operation sender.

In practical services, the operation sender (analogous to a bundler in other chains that provide account abstraction) is likely to receive User Operations created elsewhere in JSON format and then append their signature.

Therefore, when implementing actual services, use the signer.sign method to add a signature to the JSON-formatted User Operation.

For simple examples verifying the functionality of account abstraction, you may also use the operation.sign or <UserOperation>.sign methods.