code: def implied_feature (implicit_value):
      
      assert isinstance(implicit_value, basestring)
      components = implicit_value.split('-')
  
      if components[0] not in __implicit_features:
          raise InvalidValue ("'%s' is not a value of an implicit feature" % implicit_value)
  
      return __implicit_features[components[0]]
docs: Returns the implicit feature associated with the given implicit value.