Unable to use array_append function.

I tried making a custom function. Array Append

class ArrayAppend(Function):
    def __init__(self, field: str, value: typing.Any) -> None:
        super().__init__("ARRAY_APPEND", F(field), value)

# Use Case
record = await Items.filter(id=5).first()
record.orders= ArrayAppend("orders", 1234)
await record.save()

This raises a error, which is pretty self explanatory but I am not getting why this is happening..

tortoise.exceptions.OperationalError: function array_append(bigint[], integer) does not exist
HINT:  No function matches the given name and argument types. You might need to add explicit type casts.

Edit:

It magically worked, when I tried, str(int) instead of integer directly.

The issue names no repository files or tests. Start by reproducing the custom ArrayAppend call against PostgreSQL and trace how Function arguments are typed; done means the expected array_append usage is supported or the limitation is documented and covered by a regression test.