Function dict_insert_owned 

pub fn dict_insert_owned(
    dict: &mut Option<Cell>,
    key: &mut CellSlice<'_>,
    key_bit_len: u16,
    value: &dyn Store,
    mode: SetMode,
    context: &mut dyn CellContext,
) -> Result<(bool, Option<CellSliceParts>), Error>

Inserts the value associated with key in dictionary in accordance with the logic of the specified SetMode.

Returns a tuple with a new dict root, changed flag and the previous value.