You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: where_params.rs
    path of file: ./repos/prisma-client-rust/crates/generator/src/models
    
    the code of the file until where you have to start completion: use prisma_client_rust_sdk::prisma::{
    prisma_models::{
        walkers::{FieldWalker, ModelWalker, RefinedFieldWalker, ScalarFieldWalker},
        FieldArity,
    },
    psl::parser_database::ScalarFieldType,
};

use crate::prelude::*;

use super::ModelModulePart;

pub struct Operator {
    pub name: &'static str,
    pub action: &'static str,
    pub list: bool,
}

static OPERATORS: &'static [Operator] = &[
    Operator {
        name: "Not",
        action: "NOT",
        list: false,
    },
    Operator {
        name: "Or",
        action: "OR",
        list: true,
    },
    Operator {
        name: "And",
        action: "AND",
        list: false,
    },
];

#[derive(Debug)]
pub enum Variant {
    BaseVariant {
        definition: TokenStream,
        match_arm: TokenStream,
    },
    UniqueVariant {
        field_name: String,
        field_required_type: TokenStream,
        read_filter_name: String,
        optional: bool,
        value: TokenStream,
    },
    CompoundUniqueVariant {
        field_names_string: String,
        variant_data_types: Vec<TokenStream>,
        match_ar
    
pub fn unique_field_combos(model: ModelWalker) -> Vec<Vec<ScalarFieldWalker>> {
    let mut combos = model
        .indexes()
        .filter(|f| f.is_unique())
        .map(|unique| {
            unique
                .fields()
                .filter_map(|field| {
                    model
                        .scalar_fields()
                        .find(|mf| mf.field_id() == field.field_id())
                })
                .collect()
        })
        .collect::<Vec<_>>();

    if let Some(primary_key) = model.primary_key() {
        let primary_key_is_also_unique = model.indexes().any(|i| {
            primary_key.contains_exactly_fields(
                i.fields()
                    .map(|f| f.as_scalar_field())
                    .flatten()
                    .collect::<Vec<_>>()
                    .into_iter(),
            )
        });

        if !primary_key_is_also_unique {
            combos.push(
                primary_key
                    .fields()
                    .filter_map(|field| {
                        model
                            .scalar_fields()
                            .find(|mf| mf.field_id() == field.field_id())
                    })
                    .collect(),
            );
        }
    }

    combos
}