code: def bures_distance(rho0: Density, rho1: Density) -> float:
      
      fid = fidelity(rho0, rho1)
      op0 = asarray(rho0.asoperator())
      op1 = asarray(rho1.asoperator())
      tr0 = np.trace(op0)
      tr1 = np.trace(op1)
  
      return np.sqrt(tr0 + tr1 - 2.*np.sqrt(fid))
docs: Return the Bures distance between mixed quantum states
  
      Note: Bures distance cannot be calculated within the tensor backend.