with open_db() as db:
    with open_connection() as conn:
         with open("a.dat") as file1:
              with open("b.dat") as file2:
                   with getuserlock() as gu
                         do something
                          ...............
                          ...............
                          ...............
                          ...............

{
 dblinker linker;
 dbconnector connector;
 ifstream f1;f.exceptions(0xffff);f1.open("a.dat");
 ifstream f2;f.exceptions(0xffff);f2.open("b.dat");
 userlock lock;

   do something
    ...............
    ...............
    ...............
    ...............
}

with li(open_db(),
         open_connection(),
         open("a.dat"),
         open("b.dat"),
         getuserlock()) as db,file1,file2,gu:
       do something
       ...............
       ...............
       ...............
       ...............

>>> A = type('A',(object,),{})
>>> with A() as a, A() as b:
...   pass

with open_db() as db, \
     open_connection() as conn, \
     open("a.dat") as file1, \
     open("b.dat") as file2, \
     getuserlock() as gu:
    do something

with open('/etc/passwd') as f1, \
     open('/etc/profile') as f2, \
     open('/etc/bashrc') as f3:
    for a, b, c in zip(f1, f2, f3):
        print(a, b, c)