docs: def firsts(properties):
      """
      Transform a dictionary of {name: [(elt, value)+]} (resulting from
          get_properties) to a dictionary of {name, value} where names are first
          encountered in input properties.
  
      :param dict properties: properties to firsts.
      :return: dictionary of parameter values by names.
      :rtype: dict
      """
  
      result = {}
  
      # parse elts
      for name in properties:
          elt_properties = properties[name]
          # add property values in result[name]
          result[name] = elt_properties[0][1]
  
      return result