def _list_rotated_left(list_, n):
    """Return the input 'list_', rotated left by n places.

    'n' must be between zero and len(list_).

    Usage examples:

        >>> _list_rotated_left([1, 2, 3], 0)
        [1, 2, 3]
        >>> _list_rotated_left([1, 2, 3], 1)
        [2, 3, 1]
        >>> _list_rotated_left([1, 2, 3], 2)
        [3, 1, 2]

    :list_: a list.
    :n: the number of places to rotate left.
    :returns: a new list.
    """
    if n < 0:
        raise ValueError("n must be zero or greater, got {}.".format(n))
    if n > len(list_):
        raise ValueError(
            "n must be less than list len ({}), got {}.".format(len(list_), n)
        )
    return list_[n:] + list_[:n]