def METHOD_NAME(name, version, extras=None):
    """Return an internet-friendly user_agent string.
    The majority of this code has been wilfully stolen from the equivalent
    function in Requests.
    :param name: The intended name of the user-agent, e.g. "python-requests".
    :param version: The version of the user-agent, e.g. "0.0.1".
    :param extras: List of two-item tuples that are added to the user-agent
        string.
    :returns: Formatted user-agent string
    :rtype: str
    """
    if extras is None:
        extras = []
    return UserAgentBuilder(
            name, version
        ).include_extras(
            extras
        ).include_implementation(
        ).include_system().build()