code: func (ls *LocalStore) isValid(chunk Chunk) bool {
  	// by default chunks are valid. if we have 0 validators, then all chunks are valid.
  	valid := true
  
  	// ls.Validators contains a list of one validator per chunk type.
  	// if one validator succeeds, then the chunk is valid
  	for _, v := range ls.Validators {
  		if valid = v.Validate(chunk); valid {
  			break
  		}
  	}
  	return valid
  }
docs: // isValid returns true if chunk passes any of the LocalStore Validators.
  // isValid also returns true if LocalStore has no Validators.