code: def _decref_dependencies_recursive(self, term, refcounts, garbage):
          
          # Edges are tuple of (from, to).
          for parent, _ in self.graph.in_edges([term]):
              refcounts[parent] -= 1
              # No one else depends on this term. Remove it from the
              # workspace to conserve memory.
              if refcounts[parent] == 0:
                  garbage.add(parent)
                  self._decref_dependencies_recursive(parent, refcounts, garbage)
docs: Decrement terms recursively.
  
          Notes
          -----
          This should only be used to build the initial workspace, after that we
          should use:
          :meth:`~zipline.pipeline.graph.TermGraph.decref_dependencies`