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I am looking for a way to intercept instance method calls in class MyWrapper below: class SomeClass1: def a1(self): self.internal_z() return "a1" def a2(self): return "a2" def internal_z(self): return "z" class SomeClass2(SomeClass1): pass class MyWrapper(SomeClass2): # def INTERCEPT_ALL_FUNCTION_CALLS(): # result = Call_Original_Function() # self.str += result # return result def __init__(self): self.str = '' def getFinalResult(self): return self.str x = MyWrapper() x.a1() x.a2() I want to intercept all function calls make through my wrapper class. In my wrapper class I want to keep track of

I am trying to verify the difference between instance attributes and class attributes as laid out by the Python tutorial release 2.7.3 dated Nov 01, 2012, chapter 9: Classes, Page 66 last line ( source ): Valid method names of an instance object depend on its class. By definition, all attributes of a class that are function objects define corresponding methods of its instances. So in our example, x.f is a valid method reference, since MyClass.f is a function, but x.i is not, since MyClass.i is not. But x.f is not the same thing as MyClass.f — it is a method object, not a function object. I

This question already has an answer here: What is a NullPointerException, and how do I fix it? 12 answers I've tried looking at posts on this issue but am still having some trouble with this error in my code. So in the fourth line, I create an instance variable called SongDatabase to access the SongDatabase class. But when I get down to the line, SongDatabase.addNewSong(); under case 1 , I get a java.lang.NullPointerException: null error. Interface class: public class Interface { Scanner console = new Scanner(System.in); private SongDatabase SongDatabase; public static void main(String[] args)

I'm trying to create an instance of a trait using this method val inst = new Object with MyTrait This works well, but I'd like to move this creation in to a generator function, ie. object Creator { def create[T] : T = new Object with T } I'm obviously going to need the manifest to somehow fix the type erasure problems, but before I get to this, I run in to 2 questions : Even with an implicit manifest, Scala still demands that T be a trait. How do I add a restriction to create[T] so that T is a trait? If I chose to use the Class.newInstance method to create the instance dynamically rather than

I need to determine if a given Python variable is an instance of native type: str , int , float , bool , list , dict and so on. Is there elegant way to doing it? Or is this the only way: if myvar in (str, int, float, bool): # do something The best way to achieve this is to collect the types in a list of tuple called primitiveTypes and: if isinstance(myvar, primitiveTypes): ... The types module contains collections of all important types which can help to build the list/tuple. Works since Python 2.2 Not that I know why you would want to do it, as there isn't any "simple" types in Python, it's

How is it possible to have an instance of a class which is an object , without the class being a subclass of object ? here is an example: >>> class OldStyle(): pass >>> issubclass(OldStyle, object) False >>> old_style = OldStyle() >>> isinstance(old_style, object) True hamstergene In Python 2, type and class are not the same thing, specifically, for old-style classes, type(obj) is not the same object as obj.__class__ . So it is possible because instances of old-style classes are actually of a different type ( instance ) than their class: >>> class A(): pass >>> class B(A): pass >>> b = B() >>>