Return a text string describing the problem.

    Args:
      d: map returned by GetDictToFormat with  with formatting added

def FormatProblem(self, d=None):
    """Return a text string describing the problem.

    Args:
      d: map returned by GetDictToFormat with  with formatting added
    """
    if not d:
      d = self.GetDictToFormat()

    output_error_text = self.__class__.ERROR_TEXT % d
    if ('reason' in d) and d['reason']:
      return '%s\n%s' % (output_error_text, d['reason'])
    else:
      return output_error_text