Дмитрий

function Set_python_settings()
    "Настройки табов для Python, согласно рекоммендациям
    set tabstop=4
    set shiftwidth=4
    set smarttab
    set expandtab "Ставим табы пробелами
    set softtabstop=4 "4 пробела в табе
    set smartindent
    set tags=tags
"   set tags=tags.da,python.tags,twisted.tags,tags
"   set path+=~/work/da/python/**
endfunction

function Unset_python_settings()
  set tags=tags;/
endfunction

autocmd BufNewFile,BufEnter *.{py} call Set_python_settings()
autocmd BufLeave *.{py} call Unset_python_settings()

In [1]: l = []

In [2]: [l.append(i) for i in range(1, 10)]
Out[2]: [None, None, None, None, None, None, None, None, None]

In [3]: l
Out[3]: [1, 2, 3, 4, 5, 6, 7, 8, 9]