Write a Python class that extends the Progression class so that each value in the progression is the absolute value of the difference between the previous two values. You should include a constructor that accepts a pair of numbers as the first two values, using 2 and 200 as the defaults.

class Progression:

2 Iterator producing a generic progression.

3

4 Default iterator produces the whole numbers 0, 1, 2, ...

5

6

7 def init (self, start=0):

8 Initialize current to the first value of the progression.

9 self. current = start

10

11 def advance(self):

12 Update self. current to a new value.

13

14 This should be overridden by a subclass to customize progression.

15

16 By convention, if current is set to None, this designates the

17 end of a finite progression.

18

19 self. current += 1

20

21 def next (self):

22 Return the next element, or else raise StopIteration error.

23 if self. current is None: # our convention to end a progression

24 raise StopIteration( )

25 else:

26 answer = self. current # record current value to return

27 self. advance( ) # advance to prepare for next time

28 return answer # return the answer

29

30 def iter (self):

31 By convention, an iterator must return itself as an iterator.

32 return self

33

34 def print progression(self, n):

35 Print next n values of the progression.

36 print( .join(str(next(self)) for j in range(n)))