code: func (g *Genesis) MustCommit(db ethdb.Database) *types.Block {
  	block, err := g.Commit(db)
  	if err != nil {
  		panic(err)
  	}
  	return block
  }
docs: // MustCommit writes the genesis block and state to db, panicking on error.
  // The block is committed as the canonical head block.