code: def set(self, value, parse=False):
          
          self.value = self.parse(value) if parse else value
docs: Set the value of the option.
          
          One can also set the 'value' property:
  
          >>> opt = ValueOption("oname", Numeric(default=1,help="an option exemple"))
          >>> opt.value = 12
          
          :param value: the new value