def get_namespace_from_name(name):
    """
    Get a fully-qualified name's namespace, if it has one.
    It's the sequence of characters after the last "." in the name.
    If there is no "." in the name, then it belongs to the null
    namespace (i.e. the empty string will be returned)

    >>> get_namespace_from_name('abcd.efgh')
    'efgh'
    >>> get_namespace_from_name('abc')
    ''
    >>> get_namespace_from_name('a.b.c')
    'c'
    """
    if '.' not in name:
        return ''
    return name.split('.')[-1]
