fix type error in prepare_tfrecord_lib.py #1294

	name: build

	on: [push]

	jobs:
	build:
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v2
	- name: Set up Python
	uses: actions/setup-python@v2
	with:
	python-version: '3.8'
	- name: Install dependencies
	# TODO(jesseengel): Remove `legacy-resolver` when pip dependency resolution
	# is no longer broken. Currently stalls (backtracking), only on GitHub, not
	# locally.
	run: \|
	sudo apt update
	sudo apt-get -y install ffmpeg
	pip install -U pip
	pip install -e .[data_preparation,test] --use-deprecated=legacy-resolver
	- name: Test with pytest
	run: pytest
	- name: Lint with pylint
	run: pylint ddsp
	# The below step just reports the success or failure of tests as a "commit status".
	# This is needed for copybara integration.
	- name: Report success or failure as github status
	if: always()
	shell: bash
	run: \|
	status="${{ job.status }}"
	lowercase_status=$(echo $status \| tr '[:upper:]' '[:lower:]')
	curl -sS --request POST \
	--url https://api.github.com/repos/${{ github.repository }}/statuses/${{ github.sha }} \
	--header 'authorization: Bearer ${{ secrets.GITHUB_TOKEN }}' \
	--header 'content-type: application/json' \
	--data '{
	"state": "'$lowercase_status'",
	"target_url": "https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}",
	"description": "'$status'",
	"context": "github-actions/build"
	}'

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