'``expt`` is symbolic object but not equal to 0 or 1.
Expression       Result  Notes
``(-oo) ** nan`` ``nan``
``(-oo) ** oo``  ``nan``
``(-oo) ** -oo`` ``nan``
``(-oo) ** e``   ``oo``  ``e`` is positive even integer
``(-oo) ** o``   ``-oo`` ``o`` is positive odd integer
See Also
Infinity
Pow
NaN'

def _eval_power(self, expt):

    if expt.is_number:
        if ((expt is S.NaN) or (expt is S.Infinity) or (expt is S.NegativeInfinity)):
            return S.NaN
        if (isinstance(expt, Integer) and expt.is_positive):
            if expt.is_odd:
                return S.NegativeInfinity
            else:
                return S.Infinity
        return ((S.NegativeOne ** expt) * (S.Infinity ** expt))
