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: parameter.rs
    path of file: ./repos/salvo/crates/oapi/src/openapi
    
    the code of the file until where you have to start completion: //! Implements [OpenAPI Parameter Object][parameter] types.
//!
//! [parameter]: https://spec.openapis.org/oas/latest.html#parameter-object
use std::collections::HashMap;

use serde::{Deserialize, Serialize};
use serde_json::Value;

use super::{Deprecated, RefOr, Required, Schema};

/// Collection for OpenAPI Parameter Objects.
#[derive(Serialize, Deserialize, Debug, PartialEq, Default, Clone)]
pub struct Parameters(pub Vec<Parameter>);

impl IntoIterator for Parameters {
    type Item = Parameter;
    type IntoIter = <Vec<Parameter> as 
    
    fn test_parameter_merge_no_extensions() {
        let mut parameter1 = Parameter::new("param1");
        let mut parameter2 = Parameter::new("param1")
            .description("description")
            .required(Required::True)
            .deprecated(Deprecated::True)
            .schema(Schema::Object(Object::new()))
            .style(ParameterStyle::Form)
            .explode(true)
            .allow_reserved(true)
            .example(Value::String("example".to_string()));

        parameter2.extensions = Some(HashMap::from([(
            "key2".to_string(),
            Value::String("value2".to_string()),
        )]));

        assert!(parameter1.merge(parameter2));
        assert_json_eq!(
            parameter1,
            json!({
                "name": "param1",
                "in": "path",
                "description": "description",
                "required": true,
                "deprecated": true,
                "schema": {
                    "type": "object"
                },
                "style": "form",
                "explode": true,
                "allowReserved": true,
                "example": "example",
            })
        )
    }