enum scope error

// oauth.rs
extern crate reqwest;

fn getHTTPMethodString(method: reqwest::Method) -> String {
    match method {
        reqwest::Method::Options => "OPTIONS".to_string(),
        reqwest::Method::Get => "GET".to_string(),
        reqwest::Method::Post => "POST".to_string(),
    // ...
    }

// ...

pub fn generateTwitterRequest(method: reqwest::Method, ...) -> String {
    ...
}

// main.rs
extern crate reqwest;
mod oauth;

fn index() -> String {
    oauth::generateTwitterRequest(reqwest::Method::POST, ...) // GENERATES ERROR "variant not found in `reqwest::Method`"
}