text: from typing import Tuple
  
  from taco.consensus.block_record import BlockRecord
  from taco.consensus.blockchain_interface import BlockchainInterface
  from taco.util.ints import uint128
  
  
  def get_prev_transaction_block(
      curr: BlockRecord,
      blocks: BlockchainInterface,
      total_iters_sp: uint128,
  ) -> Tuple[bool, BlockRecord]:
      prev_transaction_block = curr
      while not curr.is_transaction_block:
          curr = blocks.block_record(curr.prev_hash)
      if total_iters_sp > curr.total_iters:
          prev_transaction_block = curr
          is_transaction_block = True
      else:
          is_transaction_block = False
      return is_transaction_block, prev_transaction_block
  