Function extract_attributes 

pub(crate) fn extract_attributes(
    attrs: &[Attribute],
) -> Result<(Option<U256>, Option<U256>)>

Extracts #[slot(N)], #[base_slot(N)] attributes from a field’s attributes.

This function iterates through the attributes a single time to find all relevant values. It returns a tuple containing:

• The slot number (if present)
• The base_slot number (if present)

Errors

Returns an error if:

• Both #[slot] and #[base_slot] are present on the same field
• Duplicate attributes of the same type are found