def deepcopy_minimal(item: _T) -> _T:
    """Minimal reimplementation of copy.deepcopy() that will only copy certain object types:

    - mappings, e.g. `dict`
    - list

    This is done for performance reasons.
    """
    if is_mapping(item):
        return cast(_T, {k: deepcopy_minimal(v) for k, v in item.items()})
    if is_list(item):
        return cast(_T, [deepcopy_minimal(entry) for entry in item])
    return item
Minimal reimplementation of copy.deepcopy() that will only copy certain object types:

    - mappings, e.g. `dict`
    - list

    This is done for performance reasons.
    
src/anthropic/_utils/_utils.py