message: Raise error instead unwrap in pool service send_tx.
diff: @@ -474,7 +474,9 @@ impl PoolService {
  pub fn send_tx(&self, handle: i32, json: &str) -> Result<i32, PoolError> {
  let cmd_id: i32 = SequenceUtils::get_next_id();
  - self.pools.try_borrow()?.get(&handle).unwrap().send_tx(cmd_id, json);
  + self.pools.try_borrow()?
  + .get(&handle).ok_or(PoolError::InvalidHandle("No pool with requested handle".to_string()))?
  + .send_tx(cmd_id, json);
  Ok(cmd_id)
  }
  