code: def entropy(rho: Density, base: float = None) -> float:
      
      op = asarray(rho.asoperator())
      probs = np.linalg.eigvalsh(op)
      probs = np.maximum(probs, 0.0)  # Compensate for floating point errors
      return scipy.stats.entropy(probs, base=base)
docs: Returns the von-Neumann entropy of a mixed quantum state.
  
      Args:
          rho:    A density matrix
          base:   Optional logarithm base. Default is base e, and entropy is
                  measures in nats. For bits set base to 2.
  
      Returns:
          The von-Neumann entropy of rho