def is_green_pool_free(pool):
    """
    Return True if the provided green pool is free, False otherwise.
    """
    if CONCURRENCY_LIBRARY == "eventlet":
        return pool.free()
    elif CONCURRENCY_LIBRARY == "gevent":
        return not pool.full()
    else:
        raise ValueError("Unsupported concurrency library")

    Return True if the provided green pool is free, False otherwise.
    
st2common/st2common/util/concurrency.py