def counter$($start$,$ stop$)$:

if start $>$ stop:

return$\_$string $=$ "Counting down: $"$

while $\_\_\_$ # Complete the while loop

$\_\_\_$ # Add the numbers to the "return$\_$string"

if start $>$ stop:

return$\_$string $+=","$

$\_\_\_$ # Increment the appropriate variable

else:

return$\_$string $=$ "Counting up: $"$

while $\_\_\_$ # Complete the while loop

$\_\_\_$ # Add the numbers to the "return$\_$string"

if start $<$ stop:

return$\_$string $+=","$

$\_\_\_$ # Increment the appropriate variable

return return$\_$string

print$($counter$(1,10))$ # Should be "Counting up: $1,2,3,4,5,6,7,8,9,10"$

print$($counter$(2,1))$ # Should be "Counting down: $2,1"$

print$($counter$(5,5))$ # Should be "Counting up: $5"$