Why is python telling me that a string has no atrribute "x"?

Question

def __init__(box):
    box.board = []
    with io.StringIO(text) as fp:
      for line in fp:
        box.board.append(list(line))
  def show_board (box):
    for row in box.board:
      for item in row:
        if item == "B":
          print(item, end = '', flush = True)
        else:
          print(item, end = '', flush = True)
  def detect_box_point(box):
    for y, row in enumerate(box.board):
      for x, item in enumerate(row):
        if item == "B":
          box.x, box.y = x, y

What I'm trying to do is make a pushable box, using the same set of code as the player (yes I know this is probably a stupid way I'm still new to this sort of thing), and for some reason, it keeps telling me that "str has no atrribute x" when it gets to

def move_player_box(player, move, box):
    clear()
    moved = False
    if move == "d":
      new_x = player.x + 2
      new_y = player.y
      **newbox_x = box.x + 2
      newbox_y = box.y**
      moved = True

Any help with this or any better ways to go about this?

Full code:

text = """This is just text to place the stuff"""
player = "#"
box = "B"

class Game():
  def __init__(player):
    player.board = []
    with io.StringIO(text) as fp:
      for line in fp:
        player.board.append(list(line))
  def show_board (player):
    for row in player.board:
      for item in row:
        if item == "#":
          print(item, end = '', flush = True)
        else:
          print(item, end = '', flush = True)
  def detect_start_point(player):
    for y, row in enumerate(player.board):
      for x, item in enumerate(row):
        if item == "#":
          player.x, player.y = x, y
  def __init__(box):
    box.board = []
    with io.StringIO(text) as fp:
      for line in fp:
        box.board.append(list(line))
  def show_board (box):
    for row in box.board:
      for item in row:
        if item == "B":
          print(item, end = '', flush = True)
        else:
          print(item, end = '', flush = True)
  def detect_box_point(box):
    for y, row in enumerate(box.board):
      for x, item in enumerate(row):
        if item == "B":
          box.x, box.y = x, y
  def move_player_box(player, move, box):
    global i
    clear()
    moved = False
    if move == "d":
      new_x = player.x + 2
      new_y = player.y
      newbox_x = box.x + 2
      newbox_y = box.y
      moved = True
    if move == "a":
      new_x = player.x - 2
      new_y = player.y
      newbox_x = box.x + 2
      newbox_y = box.y
      moved = True
    if move == "w":
      new_x = player.x
      new_y = player.y - 1
      newbox_x = box.x
      newbox_y = box.y - 1
      moved = True
    if move == "s":
      new_x = player.x
      new_y = player.y + 1
      newbox_x = box.x
      newbox_y = box.y + 1
      moved = True
    if moved:
      if player.board[new_y][new_x] in (' '):
        player.current = player.board[new_y][new_x]
        player.board[player.y][player.x] = ' '
        player.x = new_x
        player.y = new_y
        player.board[player.y][player.x] = "#"
      if player.board[new_y][new_x] in ('B'):
        if box.board[newbox_y][newbox_x] != ('-') and box.board[newbox_y][newbox_x] != ('|'):
          player.current = player.board[new_y][new_x]
          box.current = box.board[newbox_y][newbox_x]
          player.board[player.y][player.x] = ' '
          box.board[box.y][box.x] = ' '
          box.x = newbox_x
          box.y = newbox_y
          box.board[box.y][box.x] = "B"
          box.current = box.board[newbox_y][newbox_x]
          player.x = new_x
          player.y = new_y
          player.board[player.y][player.x] = "#"
        else:
          player.current = player.board[player.y][player.x]
          box.current = box.board[box.y][box.x]
    return

board = Game()
board.detect_start_point()
board.detect_box_point()
while(True):
  move = getkey()
  board.move_player_box(move, box)
  board.show_board()