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: roberta_tutorial.rs
    path of file: ./repos/candle-tutorial/examples
    
    the code of the file until where you have to start completion: use std::collections::HashMap;

use candle_core::{DType, Device, Index
    
    fn load(vb: VarBuilder, config: &RobertaConfig) -> Result<Self> {
        let attention_head_size = config.hidden_size / config.num_attention_heads;
        let all_head_size = config.num_attention_heads * attention_head_size;
        let dropout = Dropout::new(config.hidden_dropout_prob);
        let hidden_size = config.hidden_size;
        let query = linear(hidden_size, all_head_size, vb.pp("query"))?;
        let value = linear(hidden_size, all_head_size, vb.pp("value"))?;
        let key = linear(hidden_size, all_head_size, vb.pp("key"))?;
        Ok(Self {
            query,
            key,
            value,
            dropout,
            num_attention_heads: config.num_attention_heads,
            attention_head_size,
        })
    }