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...

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.

Write a Python program that inputs a document and then outputs a barchart

plot of the frequencies of each alphabet character that appears in

that document.