Worked on the google-research/android_world repository to enhance accessibility support by introducing a NONE state to the A11yMethod API. This update involved modifying the _process_timestep method in Python so that it returns an empty list when the NONE state is active, allowing the system to gracefully handle scenarios where no accessibility tree is available. The change improves the reliability of accessibility features, particularly for screen readers, by reducing errors and simplifying null handling. Focused on software development best practices, the work delivered a single, well-scoped feature that increases resilience and lowers maintenance costs for downstream consumers of the API.