write my assignment 2104

is_phone_num() –> is_phone_num() –> is_phone_num() –>

2.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(‘123-456-7890n’) –> ‘XXX-XXX-XXXXn’ redact_line(‘123-456-7890 123-456-78901 123-456-7890n’) –> 

‘XXX-XXX-XXXX 123-456-78901 XXX-XXX-XXXXn’ biggest: This function returns the largest value in its sole argument, a nonempty matrix.