from typing import Mapping
from typing import Any


def is_nested(item: Mapping[Any, Any]) -> bool:
    """Returns if 'item' is nested at least one-level.
    
    Args:
        item (Union[object, Type[Any]]): class or instance to examine.
        
    Returns:
        bool: if 'item' is a nested mapping.
        
    """ 
    return (
        isinstance(item, Mapping) 
        and any(isinstance(v, Mapping) for v in item.values()))