title: Powerline with Vim with ImportError: can't find appropriate configuration
body: <p>I've been trying to get <a href="https://github.com/powerline/powerline" rel="nofollow noreferrer">powerline</a> working for awhile and I can't seem to figure out what is wrong. I often use vim inside of tmux, but the error is the same inside of tmux and out.</p>
  
  <p>This is the error I get when I invoke vim:</p>
  
  <pre><code>$ vim
  Error detected while processing /Users/jlconlin/.vim/powerline.vim:
  line    4:
  Traceback (most recent call last):
    File "&lt;string&gt;", line 1, in &lt;module&gt;
  ImportError: No module named powerline.vim
  line    5:
  Traceback (most recent call last):
    File "&lt;string&gt;", line 1, in &lt;module&gt;
  NameError: name 'powerline_setup' is not defined
  line    6:
  Traceback (most recent call last):
    File "&lt;string&gt;", line 1, in &lt;module&gt;
  NameError: name 'powerline_setup' is not defined
  Press ENTER or type command to continue
  </code></pre>
  
  <p>My guess is that Vim doesn't know where to look for the python packages/modules, but I can't figure out how to tell Vim what to do. I've searched far and wide through Google (including stackexchange) and haven't found a solution. </p>
  
  <p>In my <code>.vimrc</code> file I have:</p>
  
  <pre><code>set rtp+=$POWERLINE_ROOT/powerline/bindings/vim
  let g:pymcd_powerline="py3"
  
  python from powerline.vim import setup as powerline_setup
  python powerline_setup()
  python del powerline_setup
  </code></pre>
  
  <p><code>POWERLINE_ROOT</code> is set with the command</p>
  
  <pre><code>POWERLINE_ROOT=$(pip show powerline-status | sed -n 's/Location: \(.*\)/\1/p')
  </code></pre>
  
  <p>I have installed Python3 with the anaconda distribution and I've installed powerline with pip:</p>
  
  <pre><code>$ pip show po werline-status
  Name: powerline-status
  Version: 2.7
  Summary: The ultimate statusline/prompt utility.
  Home-page: https://github.com/powerline/powerline
  Author: Kim Silkebaekken
  Author-email: kim.silkebaekken+vim@gmail.com
  License: MIT
  Location: /Users/jlconlin/opt/anaconda3/lib/python3.7/site-packages
  Requires:
  Required-by
  </code></pre>
  
  <p>I use MacVim—which has both python and python3 support—and use the internal version for my terminal vim:</p>
  
  <pre><code>$ which vim
  /Applications/MacVim.app/Contents/MacOS/vim
  
  $ vim --version
  VIM - Vi IMproved 8.1 (2018 May 18, compiled Oct 30 2019 11:57:56)
  macOS version
  Included patches: 1-2234
  Compiled by travis@Traviss-Mac.local
  Huge version with MacVim GUI.  Features included (+) or not (-):
  +acl               +file_in_path      +mouse_urxvt       -tcl
  +arabic            +find_in_path      +mouse_xterm       +termguicolors
  +autocmd           +float             +multi_byte        +terminal
  +autochdir         +folding           +multi_lang        +terminfo
  -autoservername    -footer            -mzscheme          +termresponse
  +balloon_eval      +fork()            +netbeans_intg     +textobjects
  +balloon_eval_term +fullscreen        +num64             +textprop
  +browse            -gettext           +odbeditor         +timers
  ++builtin_terms    -hangul_input      +packages          +title
  +byte_offset       +iconv             +path_extra        +toolbar
  +channel           +insert_expand     +perl/dyn          +transparency
  +cindent           +job               +persistent_undo   +user_commands
  +clientserver      +jumplist          +postscript        +vartabs
  +clipboard         +keymap            +printer           +vertsplit
  +cmdline_compl     +lambda            +profile           +virtualedit
  +cmdline_hist      +langmap           +python/dyn        +visual
  +cmdline_info      +libcall           +python3/dyn       +visualextra
  +comments          +linebreak         +quickfix          +viminfo
  +conceal           +lispindent        +reltime           +vreplace
  +cryptv            +listcmds          +rightleft         +wildignore
  +cscope            +localmap          +ruby/dyn          +wildmenu
  +cursorbind        +lua/dyn           +scrollbind        +windows
  +cursorshape       +menu              +signs             +writebackup
  +dialog_con_gui    +mksession         +smartindent       -X11
  +diff              +modify_fname      -sound             -xfontset
  +digraphs          +mouse             +spell             +xim
  +dnd               +mouseshape        +startuptime       -xpm
  -ebcdic            +mouse_dec         +statusline        -xsmp
  +emacs_tags        -mouse_gpm         -sun_workshop      -xterm_clipboard
  +eval              -mouse_jsbterm     +syntax            -xterm_save
  +ex_extra          +mouse_netterm     +tag_binary
  +extra_search      +mouse_sgr         -tag_old_static
  -farsi             -mouse_sysmouse    -tag_any_white
     system vimrc file: "$VIM/vimrc"
       user vimrc file: "$HOME/.vimrc"
   2nd user vimrc file: "~/.vim/vimrc"
        user exrc file: "$HOME/.exrc"
    system gvimrc file: "$VIM/gvimrc"
      user gvimrc file: "$HOME/.gvimrc"
  2nd user gvimrc file: "~/.vim/gvimrc"
         defaults file: "$VIMRUNTIME/defaults.vim"
      system menu file: "$VIMRUNTIME/menu.vim"
    fall-back for $VIM: "/Applications/MacVim.app/Contents/Resources/vim"
  Compilation: clang -c -I. -Iproto -DHAVE_CONFIG_H -DFEAT_GUI_MACVIM -Wall -Wno-unknown-pragmas -pipe  -DMACOS_X -DMACOS_X_DARWIN  -g -O2 -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=1
  Linking: clang   -L. -fstack-protector-strong -L/usr/local/lib -L/usr/local/opt/libyaml/lib -L/usr/local/opt/openssl@1.1/lib -L/usr/local/opt/readline/lib -L. -fstack-protector-strong -L/usr/local/lib -L/usr/local/opt/libyaml/lib -L/usr/local/opt/openssl@1.1/lib -L/usr/local/opt/readline/lib  -L/usr/local/lib -o Vim -framework Cocoa -framework Carbon       -lm  -lncurses -liconv -framework AppKit   -fstack-protector  -L/System/Library/Perl/5.18/darwin-thread-multi-2level/CORE
  </code></pre>