ariables with the degree in
        each axis given by the corresponding index.
    m : int, optional
        Number of derivatives taken, must be non-negative. (Default: 1)
    scl : scalar, optional
        Each differentiation is multiplied by `scl`.  The end result is
        multiplication by ``scl**m``.  This is for use in a linear change of
        variable. (Default: 1)
    axis : int, optional
        Axis over which the derivative is taken. (Default: 0).

        .. versionadded:: 1.7.0

    Returns
    -------
    der : ndarray
        Legendre series of the derivative.

    See Also
    --------
    legint

    Notes
    -----
    In general, the result of differentiating a Legendre 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 import legendre as L
    >>> c = (1,2,3,4)
    >>> L.legder(c)
    array([  6.,   9.,  20.])
    >>> L.legder(c, 3)
    array([60.])
    >>> L.legder(c, scl=-1)
    array([ -6.,  -9., -20.])
    >>> L.legder(c, 2,-1)
    array([  9.,  60.])

    r