Human: Slicing URL with Python Assistant: 
Here is some code to slice `url` with '&' as delimiter  to get  "http://www.domainname.com/page?CONTENT_ITEM_ID=1234" from url "http://www.domainname.com/page?CONTENT_ITEM_ID=1234&param2&param3
"

url.split('&')

#Warning: this code generation is experimental. Please inspect the code for any bugs before executing.