Check for list emptiness before checking variants #89

	name: Rpclib CI
	on:
	- push
	- pull_request
	jobs:
	run:
	name: Tests
	runs-on: ${{ matrix.operating-system }}
	strategy:
	matrix:
	# windows-latest async does not support it for now
	operating-system: [macos-latest, ubuntu-latest]
	ocaml-version: [ '4.14.0', '4.08.1' ]
	steps:
	- uses: actions/checkout@master
	- name: Setup Python
	uses: actions/setup-python@v2
	with:
	python-version: '3.x'
	- name: Cache pip
	uses: actions/cache@v2
	with:
	# This path is specific to Ubuntu
	path: ~/.cache/pip
	# Look to see if there is a cache hit
	key: ${{ runner.os }}-pip
	restore-keys: \|
	${{ runner.os }}-
	- name: Install Python dependencies
	run: pip install pylint pycodestyle
	- name: Install OCaml
	uses: ocaml/setup-ocaml@v2
	with:
	ocaml-compiler: ${{ matrix.ocaml-version }}
	- name: Install OCaml dependencies
	run: opam install -t . --deps-only
	- name: Build and test independently
	run: opam install -t rpclib rpclib-js rpclib-html rpclib-lwt rpclib-async
	- name: Run Rpc and Ppx_deriving_rpc Tests
	run: opam exec -- dune runtest -p ppx_deriving_rpc
	- name: Build and run Examples
	run: opam exec -- dune build @runexamples -p ppx_deriving_rpc

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