import requests
import pkg_resources


def pypi_versions(package_name: str):
    """
    Determine list of versions available for a package on PyPi.
    No error checking.

    :param package_name: package to search for
    :return: list of string versions
    """

    url = "https://pypi.python.org/pypi/{}/json".format(package_name)
    data = requests.get(url).json()
    return sorted(list(data["releases"].keys()), key=pkg_resources.parse_version, reverse=True)