def find_sps_between(net, source_np, target_np):
    """Return list of all direct sps from source_np to target_np.
    """
    sp_list = []
    for s,S in net["synapse_pools"].items():
        if target_np == S["target"]:
            for i in range(len(S["source"])):
                for j in range(len(S["source"][i])):
                    if source_np == S["source"][i][j] and s not in sp_list:
                        sp_list.append(s)
    return sp_list