Returns the release number of a given release code name in a
    ``<year>.<month>`` context.

    If the release name has not been given an assigned release number, the
    function returns a string. If the release cannot be found, it returns
    ``None``.

    name
        The release codename for which to find a release number.

    CLI Example:

    .. code-block:: bash

        salt '*' salt_version.get_release_number 'Oxygen'

def get_release_number(name):
    '''
    Returns the release number of a given release code name in a
    ``<year>.<month>`` context.

    If the release name has not been given an assigned release number, the
    function returns a string. If the release cannot be found, it returns
    ``None``.

    name
        The release codename for which to find a release number.

    CLI Example:

    .. code-block:: bash

        salt '*' salt_version.get_release_number 'Oxygen'
    '''
    name = name.lower()
    version_map = salt.version.SaltStackVersion.LNAMES
    version = version_map.get(name)
    if version is None:
        log.info('Version %s not found.', name)
        return None

    if version[1] == 0:
        log.info('Version %s found, but no release number has been assigned yet.', name)
        return 'No version assigned.'

    return '.'.join(str(item) for item in version)