code: def payment_begin(self, wallet):
          
  
          wallet = self._process_value(wallet, 'wallet')
  
          payload = {"wallet": wallet}
  
          resp = self.call('payment_begin', payload)
  
          return resp['account']
docs: Begin a new payment session. Searches wallet for an account that's
          marked as available and has a 0 balance. If one is found, the account
          number is returned and is marked as unavailable. If no account is
          found, a new account is created, placed in the wallet, and returned.
  
          :param wallet: Wallet to begin payment in
          :type wallet: str
  
          :raises: :py:exc:`nano.rpc.RPCException`
  
          >>> rpc.payment_begin(
          ... wallet="000D1BAEC8EC208142C99059B393051BAC8380F9B5A2E6B2489A277D81789F3F"
          ... )
          "xrb_3e3j5tkog48pnny9dmfzj1r16pg8t1e76dz5tmac6iq689wyjfpi00000000"