Line-by-line file processing

It is required to implement two functions: the first – process_dataset, which takes a filename and a processing function, reads the file line by line, and applies the given function to each line; the second – process_record, which transforms the received string: first converting it to lowercase, then replacing each 'o' character with `'z'.

def process_dataset(file_name, process_fn):
    # TODO: Implement the function
    pass

def process_record(record):
    # TODO: Implement the processing function
    # 1. Lowercase
    # 2. 0 -> z
    pass

# Test the function
process_dataset('data.txt', process_record)