code: def boardToString(self, margins=None):
          
          if margins is None:
              margins = {}
  
          b = self.board
          rg = range(b.size())
          left = ' '*margins.get('left', 0)
          s = '\n'.join(
              [left + ' '.join([self.getCellStr(x, y) for x in rg]) for y in rg])
          return s
docs: return a string representation of the current board.