new_contents: class Try:
  
      def __init__(self, value, is_success):
          self.value = value
          self.is_success = is_success
  
      def __eq__(self, other):
          return self.value == other.value and self.is_success == other.is_success
  
      @classmethod
      def of(cls, fn, *args):
          try:
              return cls(fn(*args), True)
          except Exception as e:
              return cls(e, True)
  
      def map(self, mapper):
          if self.is_success:
              return Try(
                  mapper(self.value),
                  True
              )
          return Try(self.value, False)
  
      def fold(self, mapper):
          if self.is_success:
              return Try.of(mapper, self.value)
          return self.value
  
      def on_success(self, success_callback):
          if self.is_success:
              return success_callback(self.value)
  
      def on_fail(self, fail_callback):
          if not self.is_success:
              return fail_callback(self.value)
  
      def filter(self, filterer):
          pass
subject: add try implementation