re polynomial, :math:`L_n(x)`. These sample points and
weights correctly integrate polynomials of degree :math:`2n - 1`
or less over the interval :math:`[0, \infty]` with weight function
:math:`w(x) = e^{-x}`. See 22.2.13 in [AS]_ for details.

Parameters
----------
n : int
    quadrature order
mu : bool, optional
    If True, return the sum of the weights, optional.

Returns
-------
x : ndarray
    Sample points
w : ndarray
    Weights
mu : float
    Sum of the weights

See Also
--------
scipy.integrate.fixed_quad
numpy.polynomial.laguerre.laggauss

References
----------
.. [AS] Milton Abramowitz and Irene A. Stegun, eds.
    Handbook of Mathematical Functions with Formulas,
    Graphs, and Mathematical Tables. New York: Dover, 1972.

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