How do I click a checkbox with Selenium Python, if I don't have any id which defines the checkbox?
id is by far the easiest, there are many other options to locate an element on the page.
All provided alternatives are listed here, with examples: http://selenium-python.readthedocs.org/en/latest/locating-elements.html
You can opt from a range of locating mechanisms- apart from id. You can use the name, the xpath, the css, tagname, etc. for locating a webelement.
Here is a detailed tutorial about locating mechanisms
EDIT : Here is an example where you can use Xpath to select the checkbox
AUT : Heroku App
You can select the checkboxes using xpath as :