Sorry to be bombarding you with minor bugs, but two things I notice.
There is no space around the pipe symbol between CONSTRAINTS_AS_ALTER and OID. This causes my brain to read it as CONSTRAINTS_AS_ALTEROID. Also there is an additional pipe symbol between INSERT and INHERIT.
SQL> help set ddl
SET DDL
SET DDL [[ PRETTY | SQLTERMINATOR | CONSTRAINTS | REF_CONSTRAINTS |
CONSTRAINTS_AS_ALTER|OID | SIZE_BYTE_KEYWORD | PARTITIONING |
SEGMENT_ATTRIBUTES | STORAGE | TABLESPACE | SPECIFICATION |
BODY | FORCE | INSERT | |INHERIT | RESET] ON | OFF ]
[ COLLATION_CLAUSE NEVER | ALWAYS | NON_DEFAULT ]