how bounding static method in python?

Question

I'm getting this error:
unbound method hello() must be called with A instance as first argument(got nothing instead)

import B
class A():
   @staticmethod
   def newHello():
       A.oldHello() # Here the error
       print ' world'

   def inject(self):
       A.oldHello = B.hello
       B.hello = A.newHello


  A().inject()
  B.hello()

B.py contain only a function "hello" that print "hello"

def hello():
     print 'hello'

Thanks in advance

have you tried B with A instance as it suggests? What do you get? — jollarvia
– jollarvia, Commented Sep 26, 2014 at 16:05
do you mean call oldHello(A())? that the function hello got 1 argument,0 required — user2054758
– user2054758, Commented Sep 26, 2014 at 18:06

jollarvia · Accepted Answer · 2014-09-26 19:28:15Z

1

A.oldhello() is not static. So in B's hello function is referencing A's nonstatic oldhello statically. A does in fact need an instance. I'm not too good with the decorators and how they work but maybe try declaring oldhello in the class before the function and calling it @staticmethod. I don't know if the staticness carries over if you override the method.

Try this:

class B():
    def hello(self):
        print "hello"

class A():
   @staticmethod
   def newHello(self):
       A.oldHello(self) # Here the error
       print ' world'

   def inject(self):
       A.oldHello = B.hello
       B.hello = A.newHello

A().inject()
B().hello()

edited Sep 26, 2014 at 19:28

answered Sep 26, 2014 at 18:19

jollarvia

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