code: function runSignalSetup (component, address, stateCallers) {
    const signalsAPI = makeSignalsAPI(component.signalNames, false)
    const childSignalsAPI = makeChildSignalsAPI(component.model)
    const reducers = patchReducersWithState(address, component, stateCallers.callReducer)
    const signals = patchSignals(address, component, stateCallers.callSignal)
    const methods = patchMethods(address, component, stateCallers.callMethod,
                                 reducers, signals)
    // cannot call signalSetup any earlier because it needs a reference to
    // `methods`, which must know the address
    component.signalSetup({
      methods,
      reducers,
      signals: signalsAPI,
      childSignals: childSignalsAPI,
    })
    return { signalsAPI, childSignalsAPI }
  }
docs: Run signalSetup with the component.
  @param {Object} component -
  @param {Array} address -
  @param {Object} stateCallers -
  @return {Object} Object with keys signalsAPI and childSignalsAPI.