Function get_ws_commands 

pub fn get_ws_commands(
    exchange: &str,
    msg_types: &[MessageType],
    symbols: &[String],
    subscribe: bool,
    configs: Option<&HashMap<String, String>>,
) -> Vec<String>

Translate to websocket subscribe/unsubscribe commands.

configs Some msg_type requires a config, for example, Candlestick requires an interval parameter.