code: def initial_refcounts(self, initial_terms):
          
          refcounts = self.graph.out_degree()
          for t in self.outputs.values():
              refcounts[t] += 1
  
          for t in initial_terms:
              self._decref_dependencies_recursive(t, refcounts, set())
  
          return refcounts
docs: Calculate initial refcounts for execution of this graph.
  
          Parameters
          ----------
          initial_terms : iterable[Term]
              An iterable of terms that were pre-computed before graph execution.
  
          Each node starts with a refcount equal to its outdegree, and output
          nodes get one extra reference to ensure that they're still in the graph
          at the end of execution.