I implemented the same thing as the document in section 3.1, via Python code

And I changed the code as

import pythoncom
import win32com.client
# Equity Order Entry Example
o = win32com.client.Dispatch("Redi.ORDER")#,clsctx=pythoncom.CLSCTX_LOCAL_SERVER,userName="DEMO")
# print("hello")
o.Side = 'Buy'#'SBUX'#
o.symbol = 'LCOZ0'
o.Exchange = 'DEMO DMA'#'IFCM'
o.Quantity = '1'
o.PriceType = 'Limit' #'Market' no need to place the Price
o.Price = '41.43'
o.TIF = 'Day'
o.Account = 'DEMO'
o.Ticket = 'Direct'
# Prepare a variable which can handle returned values from submit method of the order
msg = win32com.client.VARIANT(win32com.client.pythoncom.VT_BYREF | win32com.client.pythoncom.VT_VARIANT, None)
# Send an options order
result = o.Submit(msg)
print(result) # ‘True’ if order submission was successful
print(msg.value) # message from sumbit

after I run the code, it’s return message of “invalid exchange”