def add_characteristic(options)
      self.characteristics ||= []
      characteristic = CharacteristicAssertion.new
      characteristic.add_value(options)
      self.characteristics << characteristic
    end
def add_characteristic(options)
      self.characteristics ||= []
      characteristic = CharacteristicAssertion.new
      characteristic.add_value(options)
      self.characteristics << characteristic
    end
====Params
 * <tt>options</tt> - :type ('Lineage' or valid CharacteristicType), :lineage => 'Biological', etc.