code: def _check_output(self, command):
          
          try:
              if sys.version_info[0] > 2:
                  return check_output(self.base_command + command, stderr=STDOUT).decode('utf8')
              else:
                  return check_output(self.base_command + command, stderr=STDOUT)
          except CalledProcessError as command_error:
              raise GitCommandException(*command_error.args)
docs: Wrap the call to subprocess.check_output() to raise customized exceptions and always return strings.