What is Python's equivalent of Ruby's method_missing method? I tried using __getattr__ but this hook applies to fields too. I only want to intercept the method invocations. What is the Python way to do it?
There is no difference in Python between properties and methods. A method is just a property, whose type is just instancemethod, that happens to be callable (supports __call__).
If you want to implement this, your __getattr__ method should return a function (a lambda or a regular def, whatever suite your needs) and maybe check something after the call.