'A classifier uses a rule-based approach to enrich the taxonomy, for example:
c = Classifier(parents=lambda term: term.endswith("ness") and ["quality"] or [])
taxonomy.classifiers.append(c)
This tags any word ending in -ness as "quality".
This is much shorter than manually adding "roughness", "sharpness", ...
Other examples of useful classifiers: calling en.wordnet.Synset.hyponyms() or en.number().'

def __init__(self, parents=(lambda term: []), children=(lambda term: []), value=(lambda term: None)):

    self.parents = parents
    self.children = children
    self.value = value
