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: federation.rs
    path of file: ./repos/grafbase/engine/crates/engine/src/registry/resolvers
    
    the code of the file until where you have to start completion: use engine_parser::{types::Field, Positioned};
use futures_util::future::join_all;
use serde::Deserialize;
use serde_json::Value;

use super::{ResolvedValue, ResolverContext};
use crate::{
    registry::{federation::FederationResolver, NamedType},
    resolver_utils::resolve_joined_field,
    Context, ContextExt, ContextField, Error,
};

#[derive(serde::Deserialize, serde::Serialize)]
struct Representation {
    #[serde(rename = "__typ
    
pub async fn resolve_federation_entities(ctx: &ContextField<'_>) -> Result<ResolvedValue, Error> {
    let representations = Vec::<Representation>::deserialize(
        ctx.param_value_dynamic("representations", crate::resolver_utils::InputResolveMode::Default)?
            .ok_or_else(|| Error::new("The representations parameter was missing"))?,
    )
    .map_err(|error| Error::new(format!("Could not deserialize _Any: {error}")))?;

    let futures = representations.into_iter().enumerate().map(|(index, representation)| {
        let mut ctx = ctx.clone();
        ctx.path.push(index);

        async move {
            match resolve_representation(&ctx, representation).await {
                Ok(data) => data,
                Err(error) => {
                    ctx.add_error(ctx.set_error_path(error.into_server_error(ctx.item.pos)));
                    Value::Null
                }
            }
        }
    });

    Ok(ResolvedValue::new(serde_json::Value::Array(join_all(futures).await)))
}