code: func (g *Graph) TrimLowFrequencyEdges(edgeCutoff int64) int {
  	var droppedEdges int
  	for _, n := range g.Nodes {
  		for src, e := range n.In {
  			if abs64(e.Weight) < edgeCutoff {
  				delete(n.In, src)
  				delete(src.Out, n)
  				droppedEdges++
  			}
  		}
  	}
  	return droppedEdges
  }
docs: // TrimLowFrequencyEdges removes edges that have less than
  // the specified weight. Returns the number of edges removed