code: def row(self):
          
          z = self.Z
          total = 0
          if 57 <= z <= 71:
              return 8
          elif 89 <= z <= 103:
              return 9
  
          for i in range(len(_pt_row_sizes)):
              total += _pt_row_sizes[i]
              if total >= z:
                  return i + 1
          return 8
docs: Returns the periodic table row of the element.