from datetime import datetime


def olderthanhours(obj, nhours):
    """
    Returns True if obj's is older than nhours. False otherwise.
    """
    objdate = datetime.strptime(obj.last_modified, '%Y-%m-%dT%H:%M:%S.%f')
    delta = (datetime.now() - objdate)
    return (delta.seconds / 3600) + (delta.days * 24) > nhours