code: func (c *Conn) GetDN(attr, value string) (string, error) {
  	entry, err := c.SearchOne(fmt.Sprintf("(%s=%s)", attr, value), nil)
  	if err != nil {
  		return "", err
  	}
  
  	return entry.DN, nil
  }
docs: //GetDN returns the DN for the object with the given attribute value or an error if one occurred.