import xml.etree.ElementTree as ET
from typing import Sequence, Tuple


def serialise_relay_request(
    request_type: str,
    parameters: Sequence[Tuple[str, str]],
    username: str,
    password: str,
) -> bytes:
    message = ET.Element("message")
    header = ET.SubElement(message, "Header")
    ET.SubElement(header, "Security", username=username, password=password)
    body = ET.SubElement(message, "Body")
    request = ET.SubElement(body, "Request", request_type=request_type)
    for attribute, attribute_value in parameters:
        ET.SubElement(
            request,
            "Parameters",
            attribute=attribute,
            attribute_value=attribute_value,
        )
    return ET.tostring(message, encoding="utf-8", xml_declaration=True)