code: func (p *Path) BuildIterator() graph.Iterator {
  	if p.IsMorphism() {
  		panic("Building an iterator from a morphism. Bind a QuadStore with BuildIteratorOn(qs)")
  	}
  	return p.BuildIteratorOn(p.qs)
  }
docs: // BuildIterator returns an iterator from this given Path.  Note that you must
  // call this with a full path (not a morphism), since a morphism does not have
  // the ability to fetch the underlying quads.  This function will panic if
  // called with a morphism (i.e. if p.IsMorphism() is true).