Could someone modify my code to where after a series of inputs, when using end$-$call and it see that there's a trunk line connection it outputs this:

Hanging up$...$

Connection Terminated.

but when there is no connection it displays something like this:

Unable to disconnect.

I will provide the code and the main function as a picture

import json

QUIT $=$ "quit"

SWITCH$\_$CONNECT $=$ "switch$-$connect"

SWITCH$\_$ADD $=$ "switch$-$add"

PHONE$\_$ADD $=$ "phone$-$add"

NETWORK$\_$SAVE $=$ "network$-$save"

NETWORK$\_$LOAD $=$ "network$-$load"

START$\_$CALL $=$ "start$-$call"

END$\_$CALL $=$ "end$-$call"

DISPLAY $=$ "display"

HYPHEN $="-"$

def connect$\_$switchboards$($switchboards$,$ area$\_1,$ area$\_2)$:

if area$\_1$ not in switchboards:

switchboards$[$area$\_1]=\{\}$

if area$\_2$ not in switchboards:

switchboards$[$area$\_2]=\{\}$

switchboards$[$area$\_1][$area$\_2]=\{\}$

switchboards$[$area$\_2][$area$\_1]=\{\}$

def add$\_$switchboard$($switchboards$,$ area$\_$code$)$:

switchboards$[$area$\_$code$]=\{\}$

def add$\_$phone$($switchboards$,$ area$\_$code, phone$\_$number$)$:

if area$\_$code not in switchboards:

switchboards$[$area$\_$code$]=\{\}$

switchboards$[$area$\_$code$][$phone$\_$number$]=[]$

def save$\_$network$($switchboards$,$ file$\_$name$)$:

with open$($file$\_$name, $"$w$")$ as f:

json.dump$($switchboards$,$ f$)$

def load$\_$network$($file$\_$name$)$:

with open$($file$\_$name, $"$r$")$ as f:

switchboards $=$ json.load$($f$)$

return switchboards

def start$\_$call$($switchboards$,$ start$\_$area, start$\_$number, end$\_$area, end$\_$number$)$:

if start$\_$area not in switchboards or end$\_$area not in switchboards:

print$("$Invalid area code."$)$

return

start$\_$phone $=$ start$\_$number

end$\_$phone $=$ end$\_$number

if start$\_$area $==$ end$\_$area:

switchboards$[$start$\_$area$].$setdefault$($start$\_$phone, $[]).$append$($end$\_$phone$)$

print$($

f$"$Local call: $\{$start$\_$area$\}\{$start$\_$phone$\}$ and $\{$end$\_$area$\}\{$end$\_$phone$\}$ are now connected."

$)$

elif $($

switchboards$[$start$\_$area$].$get$($end$\_$area$)$ is not None

or switchboards$[$end$\_$area$].$get$($start$\_$area$)$ is not None

$)$:

if end$\_$area not in switchboards$[$start$\_$area$]$:

print$($f$"$Connecting switchboards $\{$start$\_$area$\}$ and $\{$end$\_$area$\}.")$

connect$\_$switchboards$($switchboards$,$ start$\_$area, end$\_$area$)$

switchboards$[$start$\_$area$][$start$\_$phone$].$append$($end$\_$phone$)$

switchboards$[$end$\_$area$][$end$\_$phone$].$append$($start$\_$phone$)$

print$($

f$"$Long distance call: $\{$start$\_$area$\}\{$start$\_$phone$\}$ and $\{$end$\_$area$\}\{$end$\_$phone$\}$ are now connected."

$)$

else:

print$($

f$"$Cannot connect phones: $\{$start$\_$area$\}\{$start$\_$phone$\}$ to $\{$end$\_$area$\}\{$end$\_$phone$\}."$

$)$

def end$\_$call$($switchboards$,$ start$\_$area, start$\_$number$)$:

if len$($switchboards$[$start$\_$area$][$start$\_$number$])>0$:

switchboards$[$start$\_$area$][$start$\_$number$].$pop$()$

else:

print$($f$"$No call in progress for phone $\{$start$\_$area$\}\{$start$\_$number$\}.")$

def display$\_$switchboard$($switchboards$,$ switchboard$)$:

print$($f$"$Switchboard with area code: $\{$switchboard$\}")$

print$("$Trunk lines are:"$)$

for connected$\_$area in switchboards$[$switchboard$]$:

if len$($str$($connected$\_$area$))==3$:

print$($f$"\backslash$tTrunk line connection to: $\{$connected$\_$area$\}")$

print$("$Local phone numbers are:"$)$

for phone$\_$number, connections in switchboards$[$switchboard$].$items$()$:

if len$($str$($phone$\_$number$))==7$:

if not connections:

print$($f$"\backslash$tPhone with number: $\{$phone$\_$number$\}$ is not in use."$)$

else:

for connection in connections:

print$($f$"\backslash$tPhone with number: $\{$connection$\}$ is in use."$)$

print$("$

$")$

def display$($switchboards$)$:

for switchboard in switchboards:

display$\_$switchboard$($switchboards$,$ switchboard$)$