code: func (F *Frisby) ExpectContent(content string) *Frisby {
  	Global.NumAsserts++
  	text, err := F.Resp.Text()
  	if err != nil {
  		F.AddError(err.Error())
  		return F
  	}
  	contains := strings.Contains(text, content)
  	if !contains {
  		err_str := fmt.Sprintf("Expected Body to contain %q, but it was missing", content)
  		F.AddError(err_str)
  	}
  	return F
  }
docs: // Checks the response body for the given string