#' Generic method for calculating the degree of a list of nodes in a
BN or a DBN. Calls bnlearn's degree
underneath.
I have to redefine the generic and mask the original for it to work on both
bn and dbn objects without the user having to import bnlearn.
degree(object, Nodes, ...)
the degree of the nodes
a "bn", "dbn", "bn.fit" or "dbn.fit" object
which nodes to check
additional parameters