def assign_generator_activity!(opts)
      if opts.include?(:generator_uri)
        generator_uri = opts.delete(:generator_uri)
        @entity_source =
          @generator_activity = Krikri::Activity.from_uri(generator_uri)
      end
    end
def assign_generator_activity!(opts)
      if opts.include?(:generator_uri)
        generator_uri = opts.delete(:generator_uri)
        @entity_source =
          @generator_activity = Krikri::Activity.from_uri(generator_uri)
      end
    end
Store this agent's generator activity, which is the activity that
 produced the target entities upon which the current agent will operate.

 It is assumed that the agent class will define #entity_behavior, which
 returns the class of the appropriate behavior.

 `generator_uri' can be a string or RDF::URI.

 In the future, we might want to take a `generator_activity' parameter,
 because not every activity will modify its entities with provenance
 messages; an indexing activity, in particular.  In this case an LDP URI
 representing the activity is not relevant.

 @see Krikri::Mapper::Agent
 @see Krikri::Harvester