code: def find_upstream_changed(self, kind):
          
          output = subprocess.check_output([
              'git', 'log', '{}..origin/{}'.format(self.branch_name, self.branch_name),
              '--oneline', '--name-status'
          ], cwd=self.repo_dir).decode()
          files = []
          for line in output.split('\n'):
              if line.startswith(kind):
                  files.append(os.path.join(self.repo_dir, line.split('\t', 1)[1]))
  
          return files
docs: Return list of files that have been changed upstream belonging to a particular kind of change