code: def format_explanation(explanation, original_msg=None):
      
      if not conf.is_message_introspection_enabled() and original_msg:
          return original_msg
      explanation = ecu(explanation)
      lines = _split_explanation(explanation)
      result = _format_lines(lines)
      return u('\n').join(result)
docs: This formats an explanation
  
      Normally all embedded newlines are escaped, however there are
      three exceptions: \n{, \n} and \n~.  The first two are intended
      cover nested explanations, see function and attribute explanations
      for examples (.visit_Call(), visit_Attribute()).  The last one is
      for when one explanation needs to span multiple lines, e.g. when
      displaying diffs.