code: func NewOracle(backend ethapi.Backend, params Config) *Oracle {
  	blocks := params.Blocks
  	if blocks < 1 {
  		blocks = 1
  	}
  	percent := params.Percentile
  	if percent < 0 {
  		percent = 0
  	}
  	if percent > 100 {
  		percent = 100
  	}
  	return &Oracle{
  		backend:     backend,
  		lastPrice:   params.Default,
  		checkBlocks: blocks,
  		maxEmpty:    blocks / 2,
  		maxBlocks:   blocks * 5,
  		percentile:  percent,
  	}
  }
docs: // NewOracle returns a new oracle.