write two functions use python

write two functions use python

is_phone_num: This Boolean function takes a string and returns True if it is in the format ddd- ddd-dddd,where d is adigit,False otherwise. Examplecalls:

    is_phone_num('123-456-7890')  -->  True

     is_phone_num('123-4556-7890')  -->  False

     is_phone_num('(123)456-7890')  -->  False

redact_line: This function takes a string and returns a new string that has all of the phone numbers (as defined in the previous function description) in the original string replaced by 'XXX-XXX-XXXX'. Assume that the argument ends in a newline. Phone numbers are bracketed by spaces, newlines, and/or the beginning of the string.

example:redact_line('123-456-7890\n') --> 'XXX-XXX-XXXX\n' redact_line('123-456-7890 123-456-78901 123-456-7890\n') -->

'XXX-XXX-XXXX 123-456-78901 XXX-XXX-XXXX\n' biggest: This function returns the largest value in its sole argument, a nonempty matrix.