A 'Classy' Case for Python

classy_case.py

class Case:
    """A Class to simulate case behavior in a more compact way.

    Optionaly, default value and a conditional function can be passed.
    cases and **kwargs are for flexibility since you can't have nothing
    but string keys in kwargs. They both get combined in a single switch.

    Return value for switches can be either a value or callable.
    
    Stupid thingy, I know right! :D
    """    
    def __init__(self, default=None, condition=lambda x: x, cases={}, **kwargs):
        self.condition = condition
        self.default = default
        self.switch = cases
        for k, v in kwargs.items():
            self.switch[k] = v

    def __new__(self, default=None, condition=lambda x: x, cases={}, **kwargs):
        if cases or kwargs:
            return super(Case, self).__new__(self)
        else:
            raise ValueError
        
    def add(self, key, val):
        self.switch[key] = val
        
    def __call__(self, val):
        rval = self.switch.get(self.statement(val), self.default)
        return rval(val) if callable(rval) else rval

An example:

>>> cases = {10: "It's Ten", 5: "It's Five"}
>>> mc = Case(condition=lambda x: x*5, default="Not Found", cases=cases, nine="It's Nine")
>>> mc(1)
"It's Five"
>>>mc(5)
'Not Found'