Create a function called

string$\_$operation$($my$\_$str$)$

that takes one parameter and returns a list of all substrings containing strings joined by a hyphen$(-).$ For example,

string$\_$operation$(\text{'}$The smoky hot$-$water'$)$

will return

$[\text{'}$hot$\text{'},$ 'water'$]$

and

string$\_$operation$(\text{'}$the water in the pot'$)$

will return

$[]$