class ActiveLdap::Schema::Syntaxes::DistinguishedName

def normalize_value(value)
  if value.is_a?(DN)
    value.to_s
  else
    value
  end
end

def type_cast(value)
  return nil if value.nil?
  DN.parse(value)
rescue DistinguishedNameInvalid
  value
end

def validate_normalized_value(value, original_value)
  DN.parse(value)
  nil
rescue DistinguishedNameInvalid
  $!.message
end