isGraph(cPath) {
    // Live graph instance
    if ((typeof cPath === 'object')
      && (cPath instanceof Graph
        || (Array.isArray(cPath.nodes)
          && Array.isArray(cPath.edges)
          && Array.isArray(cPath.initializers)))) {
      return true;
    }
    // Graph JSON definition
    if ((typeof cPath === 'object') && cPath.processes && cPath.connections) { return true; }
    if (typeof cPath !== 'string') { return false; }
    // Graph file path
    return (cPath.indexOf('.fbp') !== -1) || (cPath.indexOf('.json') !== -1);
  }
@param {import("fbp-graph").Graph|object|string} cPath
@returns {boolean}