def get_html_attrs_tuple_attr(attrs, attrname):
    """Returns the value of an attribute from an attributes tuple.

    Given a list of tuples returned by an ``attrs`` argument value from
    :py:meth:`html.parser.HTMLParser.handle_starttag` method, and an attribute
    name, returns the value of that attribute.

    Args:
        attrs (list): List of tuples returned by
            :py:meth:`html.parser.HTMLParser.handle_starttag` method ``attrs``
            argument value.
        attrname (str): Name of the attribute whose value will be returned.

    Returns:
        str: Value of the attribute, if found, otherwise ``None``.
    """
    response = None
    for name, value in attrs:
        if name == attrname:
            response = value
            break
    return response