def is_turn_head(sentence):
    """
    Returns *True* if *sentence* begins a new turn. *sentence* must have a
    feature called "Turn_head" with a string value of either "True" or "False".

    :param sentence: The sentence.
    :type sentence: :class:`gatenlphiltlab.Annotation`
    :rtype: bool
    """
    return sentence.features["Turn_head"].value == "True"