def insert_blank_node(node):
    bn = Node(' ')
    bn.type = NodeType.BLANK
    bn.last = node.last
    bn.next = node
    node.last.next = bn
    node.last = bn
def insert_blank_node(node):
    bn = Node(' ')
    bn.type = NodeType.BLANK
    bn.last = node.last
    bn.next = node
    node.last.next = bn
    node.last = bn