def make_signature(title=nil,description=nil, tags=nil,
is_public=nil,is_friend=nil,is_family=nil,async=nil)
args = {'api_key' => @flickr.api_key,
'auth_token' => @flickr.auth.token.token}
args['title'] = title if title
args['description'] = description if description
args['tags'] = tags.join(',') if tags
args['is_public'] = (is_public ? '1' : '0') if is_public != nil
args['is_friend'] = (is_friend ? '1' : '0') if is_friend != nil
args['is_family'] = (is_family ? '1' : '0') if is_family != nil
args['async'] = (async ? '1' : '0') if async != nil
args['api_sig'] = @flickr.sign(args)
end