code: def get_env_short(env):
    
    env_valid(env)
    if env.find(".") > -1:
      env_short, ext = env.split(".")
    else:
      env_short = env.strip(".0123456789")
    return env_short
docs: Given an env, return <env_short> if env is valid
    Args:
      env: an environment, such as "prod", "staging", "proto<N>", "mgmt.<account_alias>"
    Returns:
      the shortname of the env, such as "prod", "staging", "proto", "mgmt"
    Raises:
      ValueError if env is misformatted or doesn't name a known environment