NLTK function from string variable isn't callable [duplicate]

I have a list of related function names which I want to iterate thru, calling the function held in the variable. But no matter how I try it, I get: "TypeError: 'TweetTokenizer' object is not callable"

Following the solution in Calling a function of a module from a string with the function's name in Python (of which it is suggested this question is a duplicate), finds the functions in the nltk module and assigns them. But my resulting "tok_alg" function is still failing as not callable. Any advice on why this is happening would be appreciated.

#!/usr/bin/env python

import nltk
import os
testTxt="I'll have a Bloomin' Onion."
Tokenizers = [ 'Tweet', 'MWE', 'TreebankWord' ]

for tokenizer in Tokenizers:
    tokz = tokenizer + 'Tokenizer'

    tok_alg = getattr(nltk, tokz)()
    result = tok_alg(testTxt)

    print(result)

Listing the functions does work, viz

for tokenizer in [ TweetTokenizer(), MWETokenizer() ]:
    result = tokenizer.tokenize(testTxt)

But the suggested conversion of str variables via getattr() is not working for NLTK. While this is elegant and practical, I need the string variables for other purposes. Surely there is some way to vivify these into a function call. What am I missing?