text: import string
  
  
  class CustomNotation(str):
  
      symbols = f'{string.digits}{string.ascii_letters}'
  
      @property
      def base(self):
          return len(self.symbols)
  
      def convert_to_decimal_notation(self):
          return sum([self.symbols.index(i) * self.base ** j for j, i in enumerate(self[::-1])])
  
      def convert_from_decimal_notation(self, decimal_number: int):
          x, y = decimal_number // self.base, self.symbols[decimal_number % self.base]
          return y if x == 0 else f'{self.convert_from_decimal_notation(x)}{y}'
  