@param target $-$ the string to look for

$*$ @return An array of String objects which contains the filenames of Photo objects in

$*$ photos which contain the parameter target.

$*$

$*$ e$.$g$.$ If the photos array contained the following:

$*$ photos $=[$

$*$ Photo$($filename $=$ "catpicture$1"),$

$*$ Photo$($filename $=$ "cat$2"),$

$*$ Photo$($filename $=$ "othercatpicture"$),$

$*$ Photo$($filename $=$ "lotsofcats"$),$

$*$ Photo$($filename $=$ "dog"$),$

$*]$

$*$

$*$ Example $1$

$*$ findPhotosContaining$("$cat$")$ should return the array:

$*[$

$*$ "catpicture$1",$

$*$ "cat$2",$

$*$ "othercatpicture",

$*$ "lotsofcats"

$*]$

$*$

$*$ Example $2$

$*$ findPhotoContaining$("$picture$")$ should return the array:

$*[$

$*$ "catpicture$1",$

$*$ "othercatpicture"

$*]$

$*$

$*$ Example $3$

$*$ findPhotosContaining$("$abc$123")$ should return the array $[]$

$*$