Returns information on a package.

        Args:
            pkg_id (str): Package Id of the software/component.

        Returns:
            list: List of version numbers installed.

def pkg_version_list(self, pkg_id):
        '''
        Returns information on a package.

        Args:
            pkg_id (str): Package Id of the software/component.

        Returns:
            list: List of version numbers installed.
        '''
        pkg_data = self.__reg_software.get(pkg_id, None)
        if not pkg_data:
            return []

        if isinstance(pkg_data, list):
            # raw data is 'pkgid': [sorted version list]
            return pkg_data  # already sorted oldest to newest

        # Must be a dict or OrderDict, and contain full details
        installed_versions = list(pkg_data.get('version').keys())
        return sorted(installed_versions, key=cmp_to_key(self.__oldest_to_latest_version))