docs: def updateKronCovs(covs,Acovs,N,P):
      """
      make sure that covs and Acovs are lists
      """
      if (covs is None) and (Acovs is None):
          covs = [SP.ones([N,1])]
          Acovs = [SP.eye(P)]
  
      if Acovs is None or covs is None:
          raise Exception("Either Acovs or covs is None, while the other isn't")
  
      if (type(Acovs)!=list) and (type(covs)!=list):
          Acovs= [Acovs]
          covs = [covs]
      if (type(covs)!=list) or (type(Acovs)!=list) or (len(covs)!=len(Acovs)):
          raise Exception("Either Acovs or covs is not a list or they missmatch in length")
      return covs, Acovs