`resp` undefined if the `last_valid_block_height` is already expired

[dim-4]

In the confirm_transaction() if you pass an old blockheight (that's older than the current blockheight), the while loop does not enter so resp never gets assigned.
The else statement should in this case raise TransactionExpiredBlockheightExceededError but instead raises UnboundLocalError: cannot access local variable 'resp' where it is not associated with a value.

solana-py/src/solana/rpc/api.py

Line 1109 in 72d3cc6

if isinstance(resp, RPCError.__args__): # type: ignore

if last_valid_block_height:  # pylint: disable=no-else-return
    current_blockheight = (self.get_block_height(commitment)).value
    # FIX
    if current_blockheight > last_valid_block_height:
        raise TransactionExpiredBlockheightExceededError(f"{tx_sig} has expired: block height exceeded")
    # /FIX
    while current_blockheight <= last_valid_block_height:
        resp = self.get_signature_statuses([tx_sig])                         # <-- never gets here
        if isinstance(resp, RPCError.__args__):  # type: ignore
            raise RPCException(resp)
        resp_value = resp.value[0]
        if resp_value is not None:
            confirmation_status = resp_value.confirmation_status
            if confirmation_status is not None:
                confirmation_rank = int(confirmation_status)
                if confirmation_rank >= commitment_rank:
                    break
        current_blockheight = (self.get_block_height(commitment)).value
        sleep(sleep_seconds)
    else:
        if isinstance(resp, RPCError.__args__):
            raise RPCException(resp)
        raise TransactionExpiredBlockheightExceededError(f"{tx_sig} has expired: block height exceeded")
    return resp