docs: function ENS_1(provider, address) {
      // Ensures backwards compatibility
      if (provider.currentProvider) {
          provider = provider.currentProvider;
      }
  
      this.web3 = new Web3(provider);
      var registryContract = new this.web3.eth.Contract(registryInterface);
      if (address != undefined) {
        registryContract.options.address = address;
        this.registryPromise = Promise.resolve(registryContract);
      } else {
        this.registryPromise = new Promise((resolve) => {
          this.web3.eth.net.getId().then(function(version) {
              registryContract.options.address = registryAddresses[version];
              resolve(registryContract);
          });
        })
      }
  }