message: chore(devtools/doc/rpc): Report invalid types format
diff: @@ -28,7 +28,8 @@ def print_types(case):
  print("#### Parameters")
  newline(1)
  for item in case["types"]:
  - assert(len(item) == 1)
  + if len(item) != 1:
  + raise Exception("Invalid `types` format, expect one map for only one type: {}".format(item))
  for (key, val) in item.items():
  print(" {} - {}".format(key, val))
  