code: def log_difference(lx, ly):
      
  
      # Negative log of double-precision infinity
      li = -709.78271289338397
      diff = ly - lx
      # Make sure log-difference can succeed
      if np.any(diff >= 0):
          raise ValueError(
              'Cannot compute log(x-y), because y>=x for some elements.')
      # Otherwise evaluate log-difference
      return lx + np.log(1. - np.exp(diff))
docs: Returns log(exp(lx) - exp(ly)) without leaving log space.