Statement used to query Oracle deadlocks

I flipped through some of the previous documents and found that the SQL statement for querying the Oracle deadlock was saved. This was taught by a previous engineer.
Select/* + rule */S. username,
Decode (L. type, 'TT', 'table lock ',
'Tx ', 'row lock ',
Null) lock_level,
O. Owner, O. object_name, O. object_type,
S. Sid, S. Serial #, S. Terminal, S. Machine, S. Program, S. osuser
From v $ session S, V $ lock l, dba_objects o
Where l. Sid = S. Sid
And l. id1 = O. object_id (+)
And S. username is not null; -- kill the deadlocked session and release the alter system kill session '123'; -- the first parameter is Sid, and the second parameter is serial # There may be many deadlocks, however, after the first few locks are released, the locks may be unlocked.