"""
File: local1.py
Python allows local functions to be defined.

Below, the local function B alters the value 
of the local variable a of the enclosing 
function A.
"""

def A(n):

   def B(y):
      nonlocal a 
      a = a + 1 
      return y + a

   a = 2*n
   print("a = " + str(a))
   x = B(5) 
   x = B(x) 
   print("a = " + str(a))
   return x

r = A(2)
print ("r = " + str(r))