Fix error when subclassing #112

	# This workflow will install Python dependencies, run tests and lint with a variety of Python versions
	# For more information see: https://help.github.com/actions/language-and-framework-guides/using-python-with-github-actions

	name: Python package

	on:
	push:
	branches: [ master ]
	pull_request:
	branches: [ master ]

	jobs:
	build:
	runs-on: ubuntu-latest
	strategy:
	matrix:
	python-version: [3.6]
	steps:
	- uses: actions/checkout@v2
	- name: Set up Python ${{ matrix.python-version }}
	uses: actions/setup-python@v2
	with:
	python-version: ${{ matrix.python-version }}
	- name: Install bazel
	run: \|
	sudo apt install curl gnupg
	curl -fsSL https://bazel.build/bazel-release.pub.gpg \| gpg --dearmor > bazel.gpg
	sudo mv bazel.gpg /etc/apt/trusted.gpg.d/
	echo "deb [arch=amd64] https://storage.googleapis.com/bazel-apt stable jdk1.8" \| sudo tee /etc/apt/sources.list.d/bazel.list

	sudo apt update && sudo apt install bazel
	bazel --version
	- name: Install dependencies
	run: \|
	python -m pip install --upgrade pip
	pip install -v .
	pip install -r requirements.txt
	pip install -r requirements-test.txt
	- name: Test with bazel
	run: \|
	bazel test ml_collections/...

Provide feedback