def getInternalIntfList(ch):
    """
        Takes a chute object and uses the key:networkInterfaces to return a list of the internal
        network interfaces that will exist in the chute (e.g., eth0, eth1, ...)

        Returns:
            A list of interface names
            None if networkInterfaces doesn't exist or there is an error
    """
    intfs = ch.getCache('networkInterfaces')
    if not intfs:
        return None
    l = []
    for i in intfs:
        l.append(i['internalIntf'])
    return l
