Events – `web3.py`: AttributeError: ‘Contract’ Object Has No Attribute ‘eventFilter’

This looks to me like a race condition.

The watch callback is executed asynchronously when data matching your filter is polled from the node. Calling myEvent.watch is non-blocking and as such myEvent.stopWatching() will be called immediately afterwards.

The result you will get depends on whether the polling completes in the milliseconds before stopWatching is called.

This is non-deterministic - you might get different results each time you run it.

For web3.py==5.x.x

GethShh

The web3.geth.shh object exposes methods to interact with the RPC APIs under the shh_ namespace.

For web3.py==4.x.x

=> We have to add the following line of code in order to fix the error for the web3.py:

from web3.shh import Shh
Shh.attach(web3, "shh")

=> We also have to add the following line for web3.js. Than use shh.

var Shh = require('web3-shh');   
var shh = new Shh(Shh.givenProvider || 'http://localhost:8545'); 

Please see following solution for web3.py:

from web3 import Web3, HTTPProvider
web3 = Web3(HTTPProvider('http://localhost:8545'))

from web3.shh import Shh  # Added line
Shh.attach(web3, "shh")   # Added line

# Now we call web3.shh as we would like:

# Example
print(web3.shh.version) #5.0
kId = web3.shh.newKeyPair();    
print(kId)
print(web3.shh.getPrivateKey(kId))
...

Please see following solution for web3.js:

$ npm install web3-shh

Example code:

web3 = new Web3(new Web3.providers.HttpProvider("http://localhost:8545"));    
if(!web3.isConnected()){console.log("notconnected"); process.exit();}

var Shh = require('web3-shh');
// "Shh.providers.givenProvider" will be set if in an Ethereum supported browser.
var shh = new Shh(Shh.givenProvider || 'http://localhost:8545');

var kId = shh.newSymKey().then(console.log); //returns a valid value.