Implement an in-memory cloud storage system. Build the class incrementally; later levels must preserve all behavior from earlier levels. File names are globally unique strings, and file sizes are non-negative integers. If an operation cannot be completed, return the failure value specified for that method. ### Level 1: Basic file operations Implement: - `add_file(name: str, size: int) -> bool` - Add a new file with the given name and size. - Return `true` if the file was added. - Return `false` if a file with the same name already exists. - `copy_file(name_from: str, name_to: str) -> bool` - Copy an existing file to a new file name. - Return `true` if the copy succeeds. - Return `false` if the source file does not exist or the destination file already exists. - `get_file_size(name: str) -> int | None` - Return the file size if the file exists. - Return `None` if the file does not exist. ### Level 2: File search Implement: - `find_file(prefix: str, suffix: str) -> list[str]` - Return all files whose names start with `prefix` and end with `suffix`. - Sort results by file size in descending order. - If two files have the same size, sort them by file name in lexicographically ascending order. - Format each result as `name(size)`, for example `logs/a.txt(120)`. ### Level 3: Users and capacity limits The system has users. Each user has a storage capacity and current usage. There is also a built-in `admin` user with unlimited capacity. Calls to `add_file` from Level 1 should behave as if the `admin` user added the file. Implement: - `add_user(user_id: str, capacity: int) -> bool` - Add a user with the given capacity and zero initial usage. - Return `true` if the user was added. - Return `false` if the user already exists. - `add_file_by(user_id: str, name: str, size: int) -> int | None` - Add a file owned by `user_id`. - Return the user's remaining capacity after adding the file. - Return `None` if the user does not exist, the file name already exists, or adding the file would exceed the user's capacity. - Update `copy_file(name_from: str, name_to: str) -> bool` - The copied file must have the same owner as the source file. - The copy consumes additional capacity from that owner. - Return `false` if the owner would exceed their capacity. - `update_capacity(user_id: str, capacity: int) -> int | None` - Set the user's capacity to the new value. - If the user's current usage exceeds the new capacity, remove that user's files until usage is less than or equal to the capacity. - Remove files in order of largest size first; for ties, remove lexicographically smaller file names first. - Return the number of removed files. - Return `None` if the user does not exist. ### Level 4: Compression and decompression Compressed files use the suffix `.COMPRESSED`. Implement: - `compress_file(user_id: str, name: str) -> int | None` - The file must exist and be owned by `user_id`. - Replace the file named `name` with a compressed file named `name.COMPRESSED`. - The compressed file has size `floor(original_size / 2)` and the same owner. - Update the user's usage accordingly. - Return the user's remaining capacity. - Return `None` if the file does not exist, is not owned by the user, or the compressed destination name already exists. - `decompress_file(user_id: str, name: str) -> int | None` - The file must exist, be owned by `user_id`, and have the suffix `.COMPRESSED`. - Replace it with the original file name obtained by removing the `.COMPRESSED` suffix. - The decompressed size is `2 * compressed_size`. - Return `None` if the original file name already exists or decompression would exceed the user's capacity. - Otherwise, update the user's usage and return the user's remaining capacity.