def normalize_name(s):
    """Convert a string into a valid python attribute name.
    This function is called to convert ASCII strings to something that can pass as
    python attribute name, to be used with namedtuples.

    >>> str(normalize_name('class'))
    'class_'
    >>> str(normalize_name('a-name'))
    'a_name'
    >>> str(normalize_name('a n\u00e4me'))
    'a_name'
    >>> str(normalize_name('Name'))
    'Name'
    >>> str(normalize_name(''))
    '_'
    >>> str(normalize_name('1'))
    '_1'
    """
    s = s.replace('-', '_').replace('.', '_').replace(' ', '_')
    if s in keyword.kwlist:
        return s + '_'
    s = '_'.join(slug(ss, lowercase=False) for ss in s.split('_'))
    if not s:
        s = '_'
    if s[0] not in string.ascii_letters + '_':
        s = '_' + s
    return s
Convert a string into a valid python attribute name.
    This function is called to convert ASCII strings to something that can pass as
    python attribute name, to be used with namedtuples.

    >>> str(normalize_name('class'))
    'class_'
    >>> str(normalize_name('a-name'))
    'a_name'
    >>> str(normalize_name('a n\u00e4me'))
    'a_name'
    >>> str(normalize_name('Name'))
    'Name'
    >>> str(normalize_name(''))
    '_'
    >>> str(normalize_name('1'))
    '_1'