Oracle to PostgreSQL: Packages

In oracle you can have private variables within your package, e.g.

create or replace package examplepackage as
procedure p_set_var(val varchar2);
pragma restrict_references(p_set_var, rnps, rnds, wnds);
function f_get_var return varchar2;
pragma restrict_references(f_get_var, wnps, rnds, wnds);
end examplepackage;
/
show errors;

create or replace package body examplepackage as
privatevar varchar2(32);
procedure p_set_var(
val varchar2
) AS
begin
privatevar := val;
end;
function f_get_var return varchar2 AS
begin
return privatevar;
end;
end examplepackage;
/
show errors;

execute examplepackage.p_set_var('a');
select examplepackage.f_get_var from dual;

This allows you to effectively use session or transaction variables within your code. Is there a way to emulate this in PostgreSQL?