。
The room is cleaned by me.
Literal
Room [topic-は] me [by-によって] cleaned.
A textbook-style passive using によって to mark the agent. This sounds unnatural — a native speaker would say 私が部屋を掃除する. The によって passive is more appropriate for impersonal or large-scale actions. A learner should recognize this pattern but know it rarely appears in natural speech for personal actions.