# Convert the string representation to actual data structures (dicts and lists)data = json.loads(data_str)# Perform the desired operations on the datafor i in range(len(data)): for j in range(len(data[i])): if isinstance(data[i][j], dict): # Process dictionaries as needed pass elif isinstance(data[i][j], list): # Process lists as needed pass# Convert the updated data back to a string representationdata_str = json.dumps(data)print(data_str)```In this example, we're assuming that `data` is a JSON string containing nested dictionaries and lists. The code parses the JSON string into Python's built-in data structures (`dict`s and `list`s), performs some desired operations on those data structures (in this case, just iterating over them), and then converts the updated data back to a JSON string.Remember that JSON supports only a limited set of data types: numbers, strings, booleans, arrays, objects, and null. If your data contains other types (like dates or timestamps), you'll need to convert those to one of these supported types before serializing them as JSON. Similarly, if your data requires more advanced formatting or validation than JSON provides, you may want to consider using a different serialization format (like XML) or a dedicated library (like MessagePack).