code: def browsers(self, browser=None, browser_version=None, device=None, os=None, os_version=None):
          
          response = self.execute('GET', '/screenshots/browsers.json')
          for key, value in list(locals().items()):
              if key in ('self', 'response') or not value:
                  continue
              response = [item for item in response if match_item(key, value, item)]
          return response
docs: Returns list of available browsers & OS.