A researcher investigates a model where the observed data follows a distribution with density $f(x|\theta) = \theta^2 x e^{-\theta x}$ for $x > 0$. If the researcher derives the log-likelihood $\ell(\theta) = 2n \ln \theta + \sum \ln x_i - \theta \sum x_i$, what is the Fisher Information $I(\theta)$ for a single observation?