anchor.diff:    com_google_protobuf = fetchFromGitHub {
       owner = "protocolbuffers";
       repo = "protobuf";
  -    rev = "v3.7.0";
  -    sha256 = "0nlxif4cajqllsj2vdh7zp14ag48fb8lsa64zmq8625q9m2lcmdh";
  +    rev = "v3.13.0";
  +    sha256 = "1nqsvi2yfr93kiwlinz8z7c68ilg1j75b2vcpzxzvripxx5h6xhd";
     };
   
     bazel_skylib = fetchFromGitHub {
       owner = "bazelbuild";
       repo = "bazel-skylib";
  -    rev = "f83cb8dd6f5658bc574ccd873e25197055265d1c";
  -    sha256 = "091fb0ky0956wgv8gghy9ay3yfx6497mb72qvibf0y9dllmxyn9l";
  +    rev = "2ec2e6d715e993d96ad6222770805b5bd25399ae";
  +    sha256 = "1z2r2vx6kj102zvp3j032djyv99ski1x1sl4i3p6mswnzrzna86s";
  +  };
  +
  +  rules_python = fetchFromGitHub {
  +    owner = "bazelbuild";
  +    repo = "rules_python";
  +    rev = "c8c79aae9aa1b61d199ad03d5fe06338febd0774";
  +    sha256 = "1zn58wv5wcylpi0xj7riw34i1jjpqahanxx8y9srwrv0v93b6pqz";
  +  };
  +
  +  rules_proto = fetchFromGitHub {
  +    owner = "bazelbuild";
  +    repo = "rules_proto";
  +    rev = "a0761ed101b939e19d83b2da5f59034bffc19c12";
  +    sha256 = "09lqfj5fxm1fywxr5w8pnpqd859gb6751jka9fhxjxjzs33glhqf";
     };
   
     net_zlib = fetchurl rec {
  
positive.code:                 name = "bazel_skylib",
                  path = "${bazel_skylib}",
              )
  
              native.bind(
                  name = "zlib",
                  actual = "@net_zlib//:zlib",
              )
              http_archive(
                  name = "net_zlib",
                  build_file = "@com_google_protobuf//:third_party/zlib.BUILD",
                  sha256 = "${net_zlib.sha256}",
                  strip_prefix = "zlib-1.2.11",
  
negative.code:   '';
  
    personBUILD = writeText "BUILD" ''
      load("@rules_proto//proto:defs.bzl", "proto_library")
  
      proto_library(
          name = "person_proto",
          srcs = ["person.proto"],
  