interact with the vending machine in brownie framework
for interacting with this dapp we use brownie framework from python.
the solidity information exists in https://github.com/AlizadeAlireza/vending_machine_Solidity
the tests are in: https://github.com/AlizadeAlireza/vending_machine_brownie/blob/master/tests/test_vending_machine.py