code: func hasFilterMorphism(via interface{}, rev bool, filt []shape.ValueFilter) morphism {
  	return hasShapeMorphism(via, rev, shape.Filter{
  		From:    shape.AllNodes{},
  		Filters: filt,
  	})
  }
docs: // hasFilterMorphism is the set of nodes that is reachable via either a *Path, a
  // single node.(string) or a list of nodes.([]string) and that passes provided filters.