@classmethod
def basis(cls, deg, domain=None, window=None):
    """Series basis polynomial of degree `deg`.

        Returns the series representing the basis polynomial of degree `deg`.

        .. versionadded:: 1.7.0

        Parameters
        ----------
        deg : int
            Degree of the basis polynomial for the series. Must be >= 0.
        domain : {None, array_like}, optional
            If given, the array must be of the form ``[beg, end]``, where
            ``beg`` and ``end`` are the endpoints of the domain. If None is
            given then the class domain is used. The default is None.
        window : {None, array_like}, optional
            If given, the resulting array must be if the form
            ``[beg, end]``, where ``beg`` and ``end`` are the endpoints of
            the window. If None is given then the class window is used. The
            default is None.

        Returns
        -------
        new_series : series
            A series with the coefficient of the `deg` term set to one and
            all others zero.

        """
    if domain is None:
        domain = cls.domain
    if window is None:
        window = cls.window
    ideg = int(deg)
    if ideg != deg or ideg < 0:
        raise ValueError('deg must be non-negative integer')
    return cls([0] * ideg + [1], domain, window)
