def multi_fs_intersect(FSs1, FSs2, resultModel, usePorts=False):
    rFSs = []
    for FS1 in FSs1:
        for FS2 in FSs2:
            if (usePorts):
                if (FS1.dpid != FS2.dpid or FS1.direction != FS2.direction
                    or FS1.port_number_e < FS2.port_number_s or 
                    FS1.port_number_s > FS2.port_number_e):
                    continue
            rFS = single_fs_intersect(FS1,FS2, resultModel)
            if (usePorts and rFS):
                rFS.dpid = FS1.dpid
                rFS.direction = FS1.direction
                rFS.port_number_s = max(FS1.port_number_s,FS2.port_number_s)
                rFS.port_number_e = min(FS1.port_number_e,FS2.port_number_e)
            if (rFS):
                rFSs.append(rFS)
             
    return rFSs
intersects a list of FlowSpace-subclass objects with another such list. Return the intersection result
dataset/ETHPy150Open fp7-ofelia/ocf/optin_manager/src/python/openflow/optin_manager/flowspace/helper.py/multi_fs_intersect