def verify_transfer(giver: User, send_amount: float, prior_block: Output):
#print('1')
#print(giver.sk)
total_amount = prior_block.check_value(giver.sk)
#print('3')
if total_amount == None:
print('no amount')
raise Exception("No funds for the user exist with this block.")
if total_amount < send_amount:
print('insufficient funds')
raise Exception("Insufficient funds")
