<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def post(self):
 """API endpoint to push transactions to the Federation. Return: A ``dict`` containing the data about the transaction. """

        parser = reqparse.RequestParser()
        parser.add_argument('mode', type=parameters.valid_mode,
                            default='broadcast_tx_async')
        args = parser.parse_args()
        mode = str(args['mode'])

        pool = current_app.config['bigchain_pool']

        # `force` will try to format the body of the POST request even if the
        # `content-type` header is not set to `application/json`
        tx = request.get_json(force=True)

        try:
            tx_obj = Transaction.from_dict(tx)
        except SchemaValidationError as e:
            return make_error(
                400,
                message='Invalid transaction schema: {}'.format(
                    e.__cause__.message)
            )
        except ValidationError as e:
            return make_error(
                400,
                'Invalid transaction ({}): {}'.format(type(e).__name__, e)
            )

        with pool() as bigchain:
            try:
                bigchain.validate_transaction(tx_obj)
            except ValidationError as e:
                return make_error(
                    400,
                    'Invalid transaction ({}): {}'.format(type(e).__name__, e)
                )
            else:
                status_code, message = bigchain.write_transaction(tx_obj, mode)

        if status_code == 202:
            response = jsonify(tx)
            response.status_code = 202
            return response
        else:
            return make_error(status_code, message)