code: def is_valid_tile(self, x, y):
          
          x = int(x)
          y = int(y)
  
          if x < 0:
              return False
          if y < 0:
              return False
          if x > self.size_in_tiles.X:
              return False
          if y > self.size_in_tiles.Y:
              return False
  
          return True
docs: Check to see if the requested tile is part of the tile map.