dcoracle2 and OUT CLOB "character string buffer too small"

[Ville Vainio]

We have a PL/SQL procedure that has an OUT paramater of type CLOB.
When trying to call that function, we get

...
  File "c:\prj\dcoracle2\DCOracle2\DCOracle2.py", line 904, in
callproc
    return apply(proc, params, kw)
  File "c:\prj\dcoracle2\DCOracle2\DCOracle2.py", line 1526, in
__call__
    cursor.execute(sql,__plist=args)
  File "c:\prj\dcoracle2\DCOracle2\DCOracle2.py", line 1001, in
execute
    result = self._cursor.execute()

dco2.DatabaseError: (6502, 'ORA-06502: PL/SQL: numeric or value error:
character
 string buffer too small\nORA-06512: at line 1')

Surely, CLOB should not be a "character string buffer" and certainly
not too small. Calling the procedure from PL/SQL works correctly. Is
it a problem with dcoracle2? It is possible (-ish) to wrap the call by
a PL/SQL function of our own in order to circumvent this, but we would
still like to know what is broken & whether it can be fixed.