def build_items_html(items):
    rows = ""
    for item in items:
        rows += f"""
        <tr>
            <td>{item['name']}</td>
            <td>{item['quantity']}</td>
            <td>{item['price']}</td>
        </tr>
        """
    return rows


def build_keys_html(keys):
    if not keys:
        return ""

    rows = "<h3>Keys:</h3><ul>"
    for key in keys:
        rows += f"<li style='font-family:monospace'>{key}</li>"
    rows += "</ul>"
    return rows


def render_template(template_str, data):
    for key, value in data.items():
        template_str = template_str.replace(f"{{{{{key}}}}}", str(value))
    return template_str