@startuml
'!include https://raw.githubusercontent.com/bschwarz/puml-themes/master/themes/black-knight/puml-theme-black-knight.puml
'!include https://raw.githubusercontent.com/bschwarz/puml-themes/master/themes/hacker/puml-theme-hacker.puml
'!include https://raw.githubusercontent.com/bschwarz/puml-themes/master/themes/cerulean/puml-theme-cerulean.puml
!include https://raw.githubusercontent.com/bschwarz/puml-themes/master/themes/bluegray/puml-theme-bluegray.puml

!if %variable_exists("$THEME")
title Usecase Diagram - $THEME theme
!else
title Usecase Diagram
!endif

legend
This is my legend
it can have a long list of stuff here
and it can go on and on and on
that's about it
endlegend


skinparam BackgroundColor transparent
left to right direction
actor customer
actor clerk
rectangle checkout {
  customer -- (checkout)
  (checkout) .> (payment) : include
  (help) .> (checkout) : extends
  (checkout) -- clerk
}
@enduml


