How do I get Python Split to work properly? : I have a problem with python split which I can't figure out what I am missing that results in the split function not to work properly. I have been using similar splits before and they worked just fine.

content=open(file).read)()
Sep = content.split(r'Document [a-zA-Z0-9]{25}\n')

The file I am reading is something very easy as:

"I like coffee.

Document CLASSAR020181030eeat0000l
 
I like tea as well.

Document CLASSAR020181030eeat0000l

I like both coffee and tea."

Any help will be appreciated.