def _crossGeneRandom(genea, geneb, crossInds):
    """
    A crossover startegy where parts of two genes are randomly swapped.
    
    12347    =>    14341
    54321          52327    
    
    """
    # Be careful with copying here.
    
    aOut = genea
    aOut[crossInds] = geneb[crossInds]
    bOut = geneb
    bOut[crossInds] = genea[crossInds]
    
    return aOut, bOut