deep_clone and deep_merge for nested dicts

"""Deep-clone nested containers and merge mappings without aliasing."""
import copy
from collections.abc import Mapping
from typing import Any


def deep_clone(value: Any) -> Any:
    """Return a fully independent copy, including nested mutable items."""
    return copy.deepcopy(value)


def deep_merge(base: Any, override: Any) -> Any:
    """Merge override into a fresh copy of base; mappings recurse by key."""
    if isinstance(base, Mapping) and isinstance(override, Mapping):
        merged = {key: deep_clone(value) for key, value in base.items()}
        for key, value in override.items():
            if key in base:
                merged[key] = deep_merge(base[key], value)
            else:
                merged[key] = deep_clone(value)
        return merged
    # Lists, scalars and mismatched types: the override wins outright.
    return deep_clone(override)


if __name__ == "__main__":
    left = {"a": {"x": 1}, "tags": ["one"]}
    right = {"a": {"y": 2}, "tags": ["two"]}
    combined = deep_merge(left, right)
    print(combined)  # {'a': {'x': 1, 'y': 2}, 'tags': ['two']}
    print(combined["tags"] is not right["tags"])  # True