code: def set_tile(self, row, col, value):
             
          #print('set_tile: y=', row, 'x=', col)
          if col < 0:
              print("ERROR - x less than zero", col)
              col = 0
              #return
              
          if col > self.grid_width - 1 :
              print("ERROR - x larger than grid", col)
              col = self.grid_width - 1
              #return
              
          if row < 0:
              print("ERROR - y less than zero", row)
              row = 0
              #return
              
          if row > self.grid_height - 1:
              print("ERROR - y larger than grid", row)
              row = self.grid_height - 1
  
          self.grid[row][col] = value
docs: Set the tile at position row, col to have the given value.