he result of differentiating a Laguerre series does not
    resemble the same operation on a power series. Thus the result of this
    function may be "unintuitive," albeit correct; see Examples section
    below.

    Examples
    --------
    >>> from numpy.polynomial.laguerre import lagder
    >>> lagder([ 1.,  1.,  1., -3.])
    array([1.,  2.,  3.])
    >>> lagder([ 1.,  0.,  0., -4.,  3.], m=2)
    array([1.,  2.,  3.])

    r