def get_forward_type_for_negative(node):
    while True:
        node = node.last
        if (node is None):
            return None
        if (node.type != NodeType.BLANK):
            return node.type
def get_forward_type_for_negative(node):
    while True:
        node = node.last
        if (node is None):
            return None
        if (node.type != NodeType.BLANK):
            return node.type