connect(node: Node | Query) {
    assert(
      this.edges.indexOf(node) <= 0,
      node.id + ' is already connected to ' + this.id
    )

    assert(node !== this, 'Unable to connect node ' + node.id + ' to self.')

    this.edges.push(node)
  }
Connect another node to this instance by adding it to
the list of edges.