'Returns the integral of the square of the kernal from -inf to inf'

@property
def L2Norm(self):

    if (self._L2Norm is None):
        L2Func = (lambda x: ((self.norm_const * self._shape(x)) ** 2))
        if (self.domain is None):
            self._L2Norm = scipy.integrate.quad(L2Func, (- inf), inf)[0]
        else:
            self._L2Norm = scipy.integrate.quad(L2Func, self.domain[0], self.domain[1])[0]
    return self._L2Norm
