bn.kcv class: The bn.kcv class structure
Description
 The structure of an object of S3 class bn.kcv or bn.kcv.list.Details
 An object of class bn.kcv.list is a list whose elements are objects
  of class bn.kcv. An object of class bn.kcv is a list whose elements correspond to the
  iterations of a k-fold cross-validation. Each element contains the following
  objects: 
-  
test: an integer vector, the indexes of the observations
      used as a test set.
     
-  
fitted: an object of class bn.fit, the Bayesian network
      fitted from the training set.
     
-  
loss: the value of the loss function.  
 If the loss function requires to predict values from the test sets, each
  element also contains: 
-  
predicted: a factor or a numeric vector, the predicted values
      for the target node in the test set.
     
-  
observed: a factor or a numeric vector, the observed values
      for the target node in the test set.  
 In addition, an object of class bn.kcv has the following attributes: 
-  
loss: a character string, the label of the loss function.
     
-  
mean: the mean of the values of the loss function computed in
      the k iterations of the cross-validation, which is printed as the
      "expected loss" or averaged to compute the "average loss over the runs".
     
-  
bn: either a character string (the label of the learning
      algorithm to be applied to the training data in each iteration) or an
      object of class bn (a fixed network structure).