This scripts load yaml on the VIM using the if_python.

yaml_load.vim

function! s:load_yaml(filename)                                                                                            
python << EOS                                                                   
import vim, yaml                                                                
with open(vim.eval('a:filename'), 'r') as f:                                    
    obj = yaml.load(f)                                                          
    obj_hash = str(obj).replace('None', '{}')                                   
    vim.command('let l:ret = %s' % obj_hash)                                    
EOS                                                                             
  return l:ret                                                                  
endfunction

Require PyYAML.

pip install PyYAML