(seq: Sequence)
return seq
Reduces ``seq`` to its only element, or ``None`` if it is empty.

    >>> simplify_list([1])
    1
    >>> simplify_list([1, 2, 3])
    [1, 2, 3]
    >>> type(simplify_list([]))
    <class 'NoneType'>
Reduces ``seq`` to its only element, or ``None`` if it is empty.
Reduces seq to its only element or None if it is empty .
def simplify_list(seq: Sequence):
    """
    Reduces ``seq`` to its only element, or ``None`` if it is empty.

    >>> simplify_list([1])
    1
    >>> simplify_list([1, 2, 3])
    [1, 2, 3]
    >>> type(simplify_list([]))
    <class 'NoneType'>

    """
    if len(seq) == 1:
        return seq[0]
    if not seq:
        return None
    return seq
def simplify_list ( seq : Sequence ) : if len ( seq ) == 1 : return seq [ 0 ] if not seq : return None return seq