From documentation:

Method: find_all(pattern, <flags>, <format>, <extractions>)

Return Value: Region

Description: Returns all (non-overlapping) regions matching the regex pattern. The optional flags parameter may be sublime.LITERAL, sublime.IGNORECASE, or the two ORed together. If a format string is given, then all matches will be formatted with the formatted string and placed into the extractions list.


~ Ex.:

import sublime, sublime_plugin
 
class HelloWorldEventListener(sublime_plugin.EventListener):
    def on_post_save(self, view):
        print(view.find_all("s"))