how can i get user's name assigned to specific task

hello ,

i have four task

task1 service
task2 human : only one user assigned
task3 human : only one user assigned .
task 4 service

i want to store that both task’s user’s name into two variable at service task .
pl give me way to do that .
provide me code .
thanks

tengo el mismo problema. alguien puede ayudarme por favor. estoy usando la versión 7.3.2 gracias