fetchRawBlock :: Hash -> IO (Maybe RawBlock)
fetchRawBlock h = do
  outer <- rawBlockResult h
  case outer of
    Left _ -> return Nothing
    Right out ->
      return $ parseRawBlock out
fetchRawBlock :: Hash -> IO (Maybe RawBlock)
fetchRawBlock h = do
  outer <- rawBlockResult h
  case outer of
    Left _ -> return Nothing
    Right out ->
      return $ parseRawBlock out
fetchRawBlock h = do
  outer <- rawBlockResult h
  case outer of
    Left _ -> return Nothing
    Right out ->
      return $ parseRawBlock out