code: func (e *Exporter) getTxBuckets(blockMetas []*types.BlockMeta) error {
  	e.datum.TotalTxs = 0
  	e.datum.TxPerBlockBuckets = map[float64]uint64{}
  	if len(blockMetas) == 0 {
  		return nil
  	}
  	// Collect number of txs per block as an array of floats
  	txsPerBlock := make([]float64, len(blockMetas))
  	for i, block := range blockMetas {
  		txsPerBlock[i] = float64(block.Header.NumTxs)
  	}
  
  	e.datum.TxPerBlockBuckets, e.datum.TotalTxs = e.txPerBlockHistogramBuilder(txsPerBlock)
  	return nil
  }
docs: // Get transaction buckets