<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_session(account_info):
 """Get a boto3 sesssion potentially cross account sts assumed assumed sessions are automatically refreshed. """

    s = getattr(CONN_CACHE, '%s-session' % account_info['name'], None)
    if s is not None:
        return s
    if account_info.get('role'):
        s = assumed_session(account_info['role'], SESSION_NAME)
    else:
        s = boto3.Session()
    setattr(CONN_CACHE, '%s-session' % account_info['name'], s)
    return s