I am trying to fetch bundles from the Tangle based on their tail transaction hashes. I am trying to follow step 7 of the Pyota Tutorial

I successfully encrypted data and included it in a zero-value transaction as described in step 6. The transaction is visible in the Tangle Explorer and a nice green Confirmed tag is associated with it.

Unfortunately when I run the script and insert the Tail transaction hash of the bundle I get the following error:

Looking for bundle on the Tangle...
Traceback (most recent call last):
  File "read_encrypted_transaction.py", line 21, in <module>
    bundle = api.get_bundles([tail_hash])['bundles'][0]
  File "/home/userk/development/git/autodichiarazione_2.0/consistency_check/environ/lib/python3.6/site-packages/iota/api.py", line 721, in get_bundles
    return extended.GetBundlesCommand(self.adapter)(transaction=transaction)
  File "/home/userk/development/git/autodichiarazione_2.0/consistency_check/environ/lib/python3.6/site-packages/iota/commands/__init__.py", line 126, in __call__
    replacement = self._prepare_request(self.request)
  File "/home/userk/development/git/autodichiarazione_2.0/consistency_check/environ/lib/python3.6/site-packages/iota/commands/__init__.py", line 300, in _prepare_request
    failure_message = 'Request failed validation',
  File "/home/userk/development/git/autodichiarazione_2.0/consistency_check/environ/lib/python3.6/site-packages/iota/commands/__init__.py", line 335, in _apply_filter
    'filter_errors': runner.get_errors(with_context=True),
ValueError: Request failed validation ({'transaction': ['wrong_type']}) (`exc.context["filter_errors"]` contains more information).

What am I missing?

EDIT Here is the complete exception info:

Looking for bundle on the Tangle...
{'filter_errors': {'transaction': [{'code': 'wrong_type',
                                    'context': {'code': 'wrong_type',
                                                'filter': 'Type(TryteString, '
                                                          'bytearray, bytes, '
                                                          'str, '
                                                'key': 'transaction',
                                                'replacement': None,
                                    'exc_info': None,
                                    'message': 'list is not valid (allowed '
                                               'types: TryteString, bytearray, '
                                               'bytes, str).'}]}}

Additional Infos

pip show pyota
Name: PyOTA
Version: 2.1.0
Summary: IOTA API library for Python
Home-page: https://github.com/iotaledger/iota.py
Author: Phoenix Zerin
Author-email: [email protected]
License: MIT
Location: /home/userk/development/git/autodichiarazione_2.0/consistency_check/environ/lib/python3.6/site-packages
Requires: pysha3, requests, six, phx-filters

2 Answers 2


Thanks for including the additional info in your question!

I was about to write the answer to update to the newest PyOTA version, but you were faster with your comment.

So yes, PyOTA 2.3.0b1 should solve the issue! :)

  • Glad to accept your first answer as the solution
    – UserK
    Mar 24, 2020 at 21:17

Welcome to the IOTA StackExchange! I'm sorry (and a tad embarrassed 😅) to hear that you encountered an error during the tutorials! Hopefully we can get you back on track quickly!

The error message indicates two things:

Request failed validation ({'transaction': ['wrong_type']})

PyOTA attempted to craft a request to fetch information about the bundle, but somewhere (internally, it seems), there was a transaction parameter that had the wrong type.

This may indicate a bug in PyOTA, but we'll need a bit more context in order to get to the bottom of it, which brings me to:

(exc.context["filter_errors"] contains more information).

Virtually every exception that PyOTA raises has a context object attached to it with more information that may be relevant to the error. Could you modify your code a bit and edit your question to include the output it produces?

from pprint import pprint
    bundle = api.get_bundles([tail_hash])['bundles'][0]
except Exception as e:
   pprint(getattr(e, 'context', {}) 

I suspect this will need to be posted on PyOTA's issue tracker, but it would be good to gather more information first.

  • 2
    Thanks for the warm welcome. I might be using an old version of the library. I have updated my question with the requested information
    – UserK
    Mar 24, 2020 at 20:01
  • 2
    Solved using a newer version of the library 2.3.0b1. Mea culpa. Works like a charm. You guys have done a wonderful job. Should I accept your answer or write myself one with the solution?
    – UserK
    Mar 24, 2020 at 20:58
  • Sorry todofixthis
    – UserK
    Mar 24, 2020 at 21:17
  • Sweet as! I'm glad to hear that you were able to resolve the issue! Feel free to post your own solution as an answer and accept it — that way other visitors will have two different tools to approach this issue if they encounter it in the future 😺 Mar 24, 2020 at 22:47
  • Oh, nevermind; Levente figured it out first 😹 Mar 24, 2020 at 22:48

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