docs: def setup(self):
          """Setup does stuff only if there are no networks.
  
          This is so it only runs once at the start of the experiment. It first
          calls the same function in the super (see experiments.py in wallace).
          Then it adds a source to each network.
          """
          if not self.networks():
              super(FunctionLearning, self).setup()
              for net in self.networks():
                  self.source(network=net)