WEAP_run_model.py

import os
import win32com.client as client  # get win32com from Python package pywin32

# See WEAP API at https://www.weap21.org/WebHelp/WEAPApplication.htm
WEAP = client.Dispatch('WEAP.WEAPApplication')  # create WEAP object

# Open the area
WEAP.Areas("my area").Open()

# Set the expression
WEAP.Branch("\Demand Sites\my demand site").Variables("Demand").Expression = '5'

# Run the model
WEAP.Calculate()
        
# Load favorite and save results
WEAP.LoadFavorite("my favorite")
results_path = './my favorite results.csv'
WEAP.ExportResults(results_path, False, False, True)  # See docs or experiment with WEAP to understand options

WEAP.Quit()