docs: def addRandomEffect(self,K=None,covar_type='freeform',is_noise=False,normalize=True,Ks=None,offset=1e-4,rank=1,covar_K0=None):
          """
          Add random effect Term
          depending on self.P=1 or >1 add single trait or multi trait random effect term
          """
          if self.P==1:	self.addSingleTraitTerm(K=K,is_noise=is_noise,normalize=normalize,Ks=Ks)
          else:			self.addMultiTraitTerm(K=K,covar_type=covar_type,is_noise=is_noise,normalize=normalize,Ks=Ks,offset=offset,rank=rank,covar_K0=covar_K0)