Convert unicode into ascii recursively in nested object

unicode_to_ascii.py

def unicode_to_ascii(data):
    """"Convert all unicode string into ascii string"""
    if isinstance(data, basestring):
        return str(data)
    elif isinstance(data, collections.Mapping):
        return dict(map(unicode_to_ascii, data.iteritems()))
    elif isinstance(data, collections.Iterable):
        return type(data)(map(unicode_to_ascii, data))
    else:
        return data