Restrictions

Do not import any modules other than math and check. You are always allowed to define your own helper$/$wrapper functions, as long as they meet the assignment restrictions. Do not use Python constructs from later modules $($e$.$g$.$ fstrings, dictionaries, loops $($for or while or others$),$ zip, functions with default parameters, sorted, anything with sets or enumerators and$/$or lists, ord, chr$,$ try and except$).$ Use only the functions, methods, operations, constants and keywords as follows:

abs$,$ len, max, and min $($however keyword parameters for these functions are not allowed$)$

$-$Any method or constant in the math module

$-$Any basic arithmetic or comparison operations

$-$Any basic logical operators $($not$,$ and, or$)$

or just before the seventh digit,or before both the fourth and seventh digits.

For example, $\text{'}5198884567\text{'},\text{'}(519)8884567\text{'},\text{'}(519)888-4567\text{'},\text{'}519-8884567\text{'},\text{'}519888-4567\text{'}$ and $\text{'}519-888-4567\text{'}$ are all valid phone numbers.These typecasting operators: int$(),$ str$(),$ float$(),$ bool$(),$ and type$()$

$-$if statements $($including elif and else$)$

$-$String slicing and indexing as well as string operations using the operators above.

$-$String methods: capitalize, count, endswith, find, index, isalnum, isalpha, isdecimal, isdigit, islower, isnumeric, isspace, istitle, isupper, lower, lstrip, replace, rfind, rindex, rstrip, startswith, strip, swapcase, title, upper, zfill

$-$The operation in for strings.

$-$input and print as well as the formatting parameter end and method format. Note that all prompts must match exactly in order to obtain marks so ensure that you do not alter these prompts.

$-$Recursion

Skeleton:import check

input$\_$prompt $=$ "Please enter a valid phone number: $"$

error$\_$msg $=$ "Invalid phone number."

def phone$\_$number$()$:

##YOUR CODE GOES HERE

pass

## Test for given example $1$

check.set$\_$print$\_$exact$($error$\_$msg$)$

check.set$\_$input$("519","(519)888-4567")$

check.expect$("$Example $1",$ phone$\_$number$(),"5198884567")$

## Test for given example $2$

check.set$\_$print$\_$exact$($error$\_$msg$,$ error$\_$msg$,$ error$\_$msg$,$ error$\_$msg$)$

check.set$\_$input$("$n$","$n$","$n$","$n$")$

check.expect$("$Example $2",$ phone$\_$number$(),$ None$)$