from typing import Counter


def word_form_hapaxes(tokens):
    """
    Takes a list of tokens and returns a list of the
    wordform hapaxes (those wordforms that only appear once)

    For wordforms this is simple enough to do in plain
    Python without an NLP package, especially using the Counter
    type from the collections module (part of the Python
    standard library).
    """

    counts = Counter(tokens) 
    hapaxes = [word for word in counts if counts[word] == 1] 

    return hapaxes