from

import cobra.test 
model = cobra.test.create_test_model()

change to

import cobra.io
model = cobra.io.load_model(\"iYS1720\")

from

data_dir = cobra.test.data_dir

change to

data_dir = 'C:\Users\yahan\Anaconda3\Lib\site-packages\cobra\test\data' # your path