d scaling.
        The default value is [0, 1].
    window : (2,) array_like, optional
        Window, see `domain` for its use. The default value is [0, 1].

        .. versionadded:: 1.6.0
    symbol : str, optional
        Symbol used to represent the independent variable in string
        representations of the polynomial expression, e.g. for printing.
        The symbol must be a valid Python identifier. Default value is 'x'.

        .. versionadded:: 1.24

    Ú