docs: def execute_order(self, order_params, private_key):
          """
          This function executes the order created before it and signs the transaction to be submitted to the blockchain.
          Execution of this function is as follows::
  
              execute_order(order_params=create_order, private_key=kp)
  
          The expected return result for this function is the same as the execute_order function::
  
              {
                  'id': '4e6a59fd-d750-4332-aaf0-f2babfa8ad67',
                  'blockchain': 'neo',
                  'contract_hash': 'a195c1549e7da61b8da315765a790ac7e7633b82',
                  'address': 'fea2b883725ef2d194c9060f606cd0a0468a2c59',
                  'side': 'buy',
                  'offer_asset_id': 'c56f33fc6ecfcd0c225c4ab356fee59390af8560be0e930faebe74a6daff7c9b',
                  'want_asset_id': 'ab38352559b8b203bde5fddfa0b07d8b2525e132',
                  'offer_amount': '2000000',
                  'want_amount': '10000000000',
                  'transfer_amount': '0',
                  'priority_gas_amount': '0',
                  'use_native_token': True,
                  'native_fee_transfer_amount': 0,
                  'deposit_txn': None,
                  'created_at': '2018-08-05T10:38:37.714Z',
                  'status': 'processed',
                  'fills': [],
                  'makes': [
                      {
                          'id': 'e30a7fdf-779c-4623-8f92-8a961450d843',
                          'offer_hash': 'b45ddfb97ade5e0363d9e707dac9ad1c530448db263e86494225a0025006f968',
                          'available_amount': '2000000',
                          'offer_asset_id': 'c56f33fc6ecfcd0c225c4ab356fee59390af8560be0e930faebe74a6daff7c9b',
                          'offer_amount': '2000000',
                          'want_asset_id': 'ab38352559b8b203bde5fddfa0b07d8b2525e132',
                          'want_amount': '10000000000',
                          'filled_amount': '0.0',
                          'txn': None,
                          'cancel_txn': None,
                          'price': '0.0002',
                          'status': 'confirming',
                          'created_at': '2018-08-05T10:38:37.731Z',
                          'transaction_hash': '5c4cb1e73b9f2e608b6e768e0654649a4d15e08a7fe63fc536c454fa563a2f0f',
                          'trades': []
                      }
                  ]
              }
  
          :param order_params: Dictionary generated from the create order function.
          :type order_params: dict
          :param private_key: The Private Key (ETH) or KeyPair (NEO) for the wallet being used to sign deposit message.
          :type private_key: KeyPair or str
          :return: Dictionary of the transaction on the order book.
          """
          order_id = order_params['id']
          api_params = self.sign_execute_order_function[self.blockchain](order_params, private_key)
          return self.request.post(path='/orders/{}/broadcast'.format(order_id), json_data=api_params)