diff --git a/odoo-stubs/sql_db.pyi b/odoo-stubs/sql_db.pyi
index 4702918..042736c 100644
--- a/odoo-stubs/sql_db.pyi
+++ b/odoo-stubs/sql_db.pyi
@@ -12,8 +12,8 @@ from .tools import Callbacks
 _T = TypeVar('_T')
 _CursorT = TypeVar('_CursorT', bound=Cursor)
 
-def unbuffer(symb, cr: Cursor): ...
-def undecimalize(symb, cr: Cursor): ...
+def unbuffer(symb, cr: Cursor) -> str | None: ...
+def undecimalize(symb, cr: Cursor) -> float | None: ...
 def adapt_string(adapted: str) -> psycopg2.extensions.QuotedString: ...
 def flush_env(cr: Cursor, *, clear: bool = ...) -> None: ...
 def clear_env(cr: Cursor) -> None: ...