Failed to load a language-python package grammar

I would love to help improve the tree-sitter grammar, but I'm having some difficulties setting up a fork. Before tree-sitter, I could make changes to a language package by:

forking
cloning: git clone forked-package
linking: apm link forked-package
coding and testing

By following these steps, I now get the following error:

Failed to load a language-python package grammar

Cannot find module 'tree-sitter-python' in /Users/chbk/.atom/packages/language-python/grammars/tree-sitter-python.cson

At this point I figured I needed the tree-sitter-python node module, so I attempted to install it with npm install tree-sitter-python and I get this error:

> tree-sitter-python@0.15.0 install /Users/chbk/projects/language-python/node_modules/tree-sitter-python
> node-gyp rebuild

  CC(target) Release/obj.target/tree_sitter_python_binding/src/parser.o
  CXX(target) Release/obj.target/tree_sitter_python_binding/src/binding.o
../src/binding.cc:13:6: error: variable has incomplete type 'void'
void Init(Handle<Object> exports, Handle<Object> module) {
     ^
../src/binding.cc:13:11: error: use of undeclared identifier 'Handle'
void Init(Handle<Object> exports, Handle<Object> module) {
          ^
../src/binding.cc:13:18: error: 'Object' does not refer to a value
void Init(Handle<Object> exports, Handle<Object> module) {
                 ^
/Users/chbk/Library/Caches/node-gyp/12.9.1/include/node/v8.h:3369:17: note: 
      declared here
class V8_EXPORT Object : public Value {
                ^
../src/binding.cc:13:26: error: use of undeclared identifier 'exports'
void Init(Handle<Object> exports, Handle<Object> module) {
                         ^
../src/binding.cc:13:35: error: use of undeclared identifier 'Handle'
void Init(Handle<Object> exports, Handle<Object> module) {
                                  ^
../src/binding.cc:13:42: error: 'Object' does not refer to a value
void Init(Handle<Object> exports, Handle<Object> module) {
                                         ^
/Users/chbk/Library/Caches/node-gyp/12.9.1/include/node/v8.h:3369:17: note: 
      declared here
class V8_EXPORT Object : public Value {
                ^
../src/binding.cc:13:50: error: use of undeclared identifier 'module'
void Init(Handle<Object> exports, Handle<Object> module) {
                                                 ^
../src/binding.cc:13:57: error: expected ';' after top level declarator
void Init(Handle<Object> exports, Handle<Object> module) {
                                                        ^
                                                        ;
8 errors generated.
make: *** [Release/obj.target/tree_sitter_python_binding/src/binding.o] Error 1
gyp ERR! build error 
gyp ERR! stack Error: `make` failed with exit code: 2
gyp ERR! stack     at ChildProcess.onExit (/usr/local/lib/node_modules/npm/node_modules/node-gyp/lib/build.js:196:23)
gyp ERR! stack     at ChildProcess.emit (events.js:209:13)
gyp ERR! stack     at Process.ChildProcess._handle.onexit (internal/child_process.js:272:12)
gyp ERR! System Darwin 18.7.0
gyp ERR! command "/usr/local/Cellar/node/12.9.1/bin/node" "/usr/local/lib/node_modules/npm/node_modules/node-gyp/bin/node-gyp.js" "rebuild"
gyp ERR! cwd /Users/chbk/projects/language-python/node_modules/tree-sitter-python
gyp ERR! node -v v12.9.1
gyp ERR! node-gyp -v v5.0.3
gyp ERR! not ok 
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! tree-sitter-python@0.15.0 install: `node-gyp rebuild`
npm ERR! Exit status 1
npm ERR! 
npm ERR! Failed at the tree-sitter-python@0.15.0 install script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     /Users/chbk/.npm/_logs/2019-09-02T18_48_38_064Z-debug.log

I'm on macOS 10.14.6 What am I doing wrong?

atom / language-python

Failed to load a language-python package grammar #310