code: def record_diff(lhs, rhs):
      "Diff an individual row."
      delta = {}
      for k in set(lhs).union(rhs):
          from_ = lhs[k]
          to_ = rhs[k]
          if from_ != to_:
              delta[k] = {'from': from_, 'to': to_}
  
      return deltf record_diff(lhs, rhs):
      "Diff an individual row."
      delta = {}
      for k in set(lhs).union(rhs):
          from_ = lhs[k]
          to_ = rhs[k]
          if from_ != to_:
              delta[k] = {'from': from_, 'to': to_}
  
      return delta
docs: Diff an individual row.