``` vim
function! s:MapIfUnmapped(key, mapping)
  if ! hasmapto(a:mapping)
    execute 'nnoremap <Leader>'.a:key.' '.a:mapping
  endif
endfunction

call s:MapIfUnMapped('a', ':RunCurrentSpecFile<CR>')
call s:MapIfUnMapped('l', ':RunFocusedSpec<CR>')
call s:MapIfUnMapped('r', ':RunMostRecentSpec<CR>')
```

I like the readability of the mapping calls, but this may be more effort than worth it.