This is the self-custom vim snippet associated with Ultsnippets. Please place it in the .vim file in home directory.
To assure some python function work appropriately,users should run the following command in terminal.
ln -s ~/.vim/my-snippets/UltiSnips/useful_func.py ~/.vim/pythonx/useful_func.py or ln -s /my-snippets/UltiSnips/useful_func.py ~/.vim_runtime/my_plugins/vim-snippets/pythonx/useful_func.py or cp $(pwd)/.vim/my-snippets/UltiSnips/useful_func.py $(pwd)/.vim_runtime/sources_non_forked/vim-snippets/pythonx/useful_func.py

when you using amix.vim