PYTHON PROGRAMMING

Imagine a customer in a bank is asked to enter a whole number representing their approximate monetary worth. In that case, some people use commas to separate thousands, millions etc, and some dont. In order to perform a some calculations the bank needs that number as na integer. Write a function, called casual_number(s) that has one parameter, s, as input where s is a string. Function casual_number(s) should return an integer representing a number in s. If s does not look like a number the function should return None. Note that if a string in s looks like a number but with commas, you may assume that commas are in meaningful places i.e. you may assume that s will not be a string like 1, 1, 345.

>>> TESTING CODE:

>>> casual_number("251")

251

>>> casual_number("1,aba,251")

>>> casual_number("1,251")

1251

>>>casual_number("1251")

1251

>>> casual_number("-97,251")

-97251

>>> casual_number("-97251")

-97251

>>> casual_number("-,,,,")

>>> casual_number("--97,251")

>>> casual_number("-")

>>> casual_number("-1,000,001")

-1000001

>>> casual_number("999,999,999,876")

999999999876

>>> casual_number("-2")

-2