Cannot download free app that is not purchased

Hello, trying to use the "download" function with the following app:

com.facebook.orca

I receive the following error:

  File "/scripts/get_apk.py", line 29, in download_apk
    download = server.download(packageName=package_name, versionCode=int(package_version), expansion_files=True)
  File "/home/developer/workspace/gpapi/googleplay.py", line 703, in download
    return self.delivery(packageName, versionCode, offerType, dlToken,
  File "/home/developer/workspace/gpapi/googleplay.py", line 628, in delivery
    raise RequestError('App not purchased')
gpapi.googleplay.RequestError: 'App not purchased'

How can I purchase the app automatically? Is there a function to do it?

download already calls purchase:

googleplay-api/gpapi/googleplay.py

Lines 617 to 620 in 664c399

	response = requests.post(PURCHASE_URL, headers=headers,
	params=params, verify=ssl_verify,
	timeout=60,
	proxies=self.proxies_config)

so code might have an error. if it helps, I have another tool here:

https://github.com/1268/google

[0xr0n0]

Yes, the code might have an error like you said.